Important Questions For You!

Chapter 1: Periodic Table, Periodic Properties and Variations of Properties

1. Define the following terms:                                                                                                                                  [3M]

1. Ionisation potential
2. Electronaffinity
3. Electronegativity

2. In Period 3 of the periodic table, Element B is placed to the left of Element A. On the basis of this information, choose the correct word from the brackets to complete the following statements:                                                                                     [3M]

1. Element B would have (lower/higher) metallic character than Element A.
2. Element A would probably have (lesser/higher) electron affinity than Element B.
3. Element A would have (greater/smaller) atomic size than Element B.

3. An element has an atomic number 16.State                                                                                                            [3M]

1. the period to which it belongs
2. the number of valence electrons
3. whether it is a metal or non-metal

4. Give reasons:                                                                                                                                                      [3M]

1. The oxidising power of elements increases on moving from left to right along a period in the periodic table.
2. Ionisation potential of the element increases across a period.
3. Alkali metals are good reducing agents.

5. Use the letters only written in the periodic table given below to answer the questions that follow:                              [4M]

1. State the number of valence electrons in atom J.
2. Which element as shown forms ions with a single negative charge?
3. Which metal element is more reactive than R?
4. Which element has its electrons arranged in four shells?

6. Arrange the following as per the instructions given in the brackets:                                                                          [4M]

1. Cs, Na, Li, K, Rb (increasing order of metallic character)
2. Mg, Cl, Na, S, Si (decreasing order of atomic size)
3. Na, K, Cl, S, Si (increasing order ionisation energy)
4. Cl, F, Br, I (increasing order of electron affinity)

7. A group of elements in the periodic table is given below: (Boron is the first member of the group and thallium is the last.)
Boron, Aluminium, Gallium, Indium, Thallium Answer the following questions in relation to the above group of elements:   [5M]

1. Which element has the most metallic character?
2. Which element would be expected to have the highest electronegativity?
3. If the electronic configuration of aluminium is 2, 8, 3, how many electrons will there be in the outermost shell of thallium?
4. The atomic number of boron is 5. Write the chemical formula of the compound formed when boron reacts with chlorine.
5. Will the elements in the group to the right of this boron group be more metallic or less metallic in character? Justify your answer.

8. An element has 2 electrons in its N shell.                                                                                                                 [4M]

1. What is its atomic number?
2. State its position in the periodic table.
3. Is it a metal or non-metal?
4. State the name assigned to this group.

Chapter 2: Chemical Bonding

1. What is the difference between                                                                                                                               [3M]

1. Ionic compounds and polar covalent compounds
2. Ionic compounds and covalent compounds
3. Polar covalent compounds and non-polar covalent compounds

2.                                                                                                                                                                            [3M]

1. What are redox reactions?
2. Why is the reaction between manganese dioxide and hydrochloric acid a redox reaction?
3. Identify the substance oxidised and the substance reduced in the above reaction.

3.                                                                                                                                                                           [3M]

1. State the type of bonding in the following molecules:
   a) Ammonia
   b) Calcium oxide
2. Draw an electron dot diagram to show the formation of each of the following compounds:

1. Methane
2. Magnesium chloride
   [H = 1, C = 6, Mg = 12, Cl = 17]

4. Draw the orbit structure and electron dot diagrams of                                                                                            [3M]
(i) NaCl (ii) MgCl₂ (iii) CaO

5. A compound has the formula H₂Y (Y= non-metal). State the following:                                                                    [4M]

1. Outer electronic configuration of Y
2. Valency of Y
3. Bonding present in H₂Y
4. Formula of the compound formed between calcium[20Ca 40 ] and Y

6. Predict the type of bonding in the following molecules:                                                                                            [5M]

1. Oxygen
2. Calcium oxide
3. Water
4. Methane
5. Ammonium ion

Chapter 3: Acids, Bases and Salts

1. Give balanced chemical equations for the following:                                                                                                 [3M]

1. Magnesium with Hydrochloric Acid
2. Sulphuric acid with Sodium hydroxide
3. Sodium with Sulphuric acid

2. Why don you use universal indicator, you see that solutions of different acids produce different colours. Indeed, solution of the same acid with different concentrations will also give different colours. Why?                                                                 [3M]

3. Define the following as per ionic theory with examples and ionic equations wherever relevant.                                     [3M]

1. Acid
2. Base
3. Alkali

4.                                                                                                                                                                             [3M]

1. What is the pH of pure water?
2. What is the purpose of the pH scale?
3. A is a soluble acidic oxide and B is a soluble base. On comparing to the pH of water, what will be the pH of solution A and solution B?

5. You have been provided with three test tubes. One of them contains distilled water and the other two have an acidic solution and a basic solution respectively. If you are given red litmus paper, how will you identify the contents of each test tube?         [4M]

6. Give one example in each case:                                                                                                                              [5M]

1. A basic oxide which is soluble in water.
2. A hydroxide which is highly soluble in water.
3. A basic oxide which is insoluble in water.
4. A hydroxide which is insoluble in water.
5. A weak mineral acid.
6. A base which is not an alkali.
7. An oxide which is a base.
8. A hydrogen-containing compound which is not an acid.

7. Give one example in case-                                                                                                                                     [5M]

1. A basic oxide which is soluble in water.
2. A hydroxide which is highly soluble in water.
3. A basic oxide which is insoluble in water.
4. A hydroxide which is insoluble in water.
5. A weak mineral acid.
6. A base which is not alkali.
7. An oxide which is a base.
8. An oxide which is acid.
9. A hydrogen containing compound which is not an acid.
10. A base which does not contain a metal ion.

Chapter 4: Analytical Chemistry – Use of Ammonium Hydroxide and Sodium Hydroxide

1. Identify the salts P and Q from the observations below:                                                                                          [2M]

1. On performing the flame test, salt P produces a lilac-coloured flame and its solution gives a white precipitate with silver nitrate solution, which is soluble in ammonium hydroxide solution.
2. When dilute HCl is added to salt Q, a brisk effervescence is produced and the gas turns limewater milky.When NH₄OH solution is added to the above mixture (after adding dilute HCl), it produces a white precipitate which is soluble in excess NH₄OH solution.

2. State your observations when ammonium hydroxide solution is added drop by drop and in excess to each of the following solutions:                                                                                                                                                                [2M]

1. Copper sulphate solution
2. Zinc sulphate solution

3. Identify the cations in each of the following cases:                                                                                                 [3M]

1. NaOH solution when added to Solution (A) gives a reddish brown precipitate.
2. NH₄OH solution when added to Solution (B) gives a white precipitate which does not dissolve in excess.
3. NaOH solution when added to Solution (C) gives a white precipitate which is insoluble in excess.

4. Give a chemical test to distinguish between the following pairs of chemicals:                                                             [4M]

1. Lead nitrate solution and zinc nitrate solution
2. Sodium chloride solution and sodium nitrate solution
3. Ammonium hydroxide and sodium hydroxide
4. Dilute sulphuric acid and dilute hydrochloric acid

5. The following table shows the test a student performed on four aqueous solutions X, Y, Z and W. Based on the observations provided, identify the  cation present:                                                                                                                         [4M]

Chapter 5: Mole Concept and Stoichiometry

1. Calculate the number of gram atoms in 4.6 grams of sodium (Na = 23)                                                                  [2M]

2. A gaseous hydrocarbon contains 82.76% of carbon. Given that its vapour density is 29, find its molecular formula. [C = 12, H = 11]                                                                                                                                                                       [2M]

3. Calculate the percentage of water of crystallization in CuSO₄.5H₂O
(H = 1, O = 16, S = 32, Cu = 64)                                                                                                                            [2M]

4. A compound of X and Y has the empirical formula XY2. Its vapour density is equal to its empirical formula weight. Determine its molecular formula.                                                                                                                                                  [3M]

5. A cylinder contains 68 g of ammonia gas at STP.                                                                                                    [3M]

1. What is the volume occupied by this gas?
2. How many moles of ammonia are present in the cylinder?
3. How many molecules of ammonia are present in the cylinder?
   [N = 14, H = 1]

6. The mass of 11.2 litres of a certain gas at STP is 24 g. Find the gram molecular mass of the gas.                               [3M]

7. A gas cylinder can hold 1 kg of hydrogen at room temperature and pressure.                                                            [2M]

1. Find the number of moles of hydrogen present.
2. What weight of CO₂ can the cylinder hold under similar conditions of temperature and pressure? (Atomic masses: H = 1, C = 12, O = 16)

Chapter 6: Electrolysis

1. Give reasons why.                                                                                                                                               [3M]

1. Sodium chloride will conduct electricity only in the fused or aqueous solution state.
2. In the electroplating of an article with silver, the electrolyte sodium argentocyanide solution is preferred over silver nitrate solution.
3. Although copper is a good conductor of electricity, it is a non-electrolyte.

2. Three electrolytic cells A, B and C are connected in separate circuits. Electrolytic cell A contains sodium chloride solution. When the circuit is completed, a bulb in the circuit glows brightly. Electrolytic cell B contains acetic acid solution, and here, the bulb in the circuit glows dimly. The electrolytic cell C contains sugar solution, and the bulb does not glow. Give reason for each of these observations.                                                                                                                                                            [3M]

3. State the observations at the anode and cathode during the electrolysis of                                                                  [3M]

1. Fused lead bromide using graphite electrodes
2. Copper sulphate solution using copper electrodes

4. The following questions are related to the electroplating of an article with silver:                                                           [4M]

1. Name the electrode formed by the article to be plated.
2. Which ion must be present in the article to be plated?
3. Name the electrolyte used for the electroplating of the article with silver.
4. Give the application of electrolysis.

5. Answer the following questions about the electroplating of copper wire with silver:                                                        [4M]

1. What ions must be present in the electrolyte?
2. Of what substance must the anode be made?
3. What will be made the cathode?
4. What is the equation for the reaction which takes place at the cathode?

Chapter 7: Metallurgy
1.                                                                                                                                                                               [2M]

1. Name the most common ore of the metal aluminium from which the metal is extracted. Write the chemical formula of the ore.
2. (Name the process by which the impure ore of aluminium is purified by using a concentrated solution of an alkali.

2. Answer the following questions                                                                                                                                  [2M]

1. Give the balanced equation for the reaction between iron oxide (III) and carbon monoxide.
2. Explain why powdered coke is sprinkled over the electrolytic mixture.

3. For each of the substances listed below, describe the role played in the extraction of aluminium.                                    [3M]

1. Cryolite
2. Sodium hydroxide
3. Graphite 

4.                                                                                                                                                                               [5M]

1. Give the name and formula of the ore of zinc.
2. Write equations for the following steps in the extraction of zinc:
   i. Roasting of ore
   ii. Reduction of zinc compound which is the product of the above reaction.
3. What is add into the blast furnace in addition to zinc compound?
4. State one large scale use of zinc.
5. Name the process by which zinc is purified.

5. Name the following:                                                                                                                                                [4M]

1. Process of coating of iron with zinc.
2. Alloy of lead and tin which is used in electrical circuits.
3. Ore of zinc containing its sulphide.
4. Metal oxide which can be reduced by hydrogen.

6.                                                                                                                                                                               [4M]

1. Name the solution used to react with bauxite as a first step in obtaining pure aluminium oxide in Bayer’s process.
2. Write the equation for the reaction where aluminium oxide for the electrolytic extraction of aluminium is obtained by heating aluminium hydroxide.
3. Name the compound added to pure alumina to lower the fusion temperature during the electrolytic reduction of alumina.
4. Write the equation for the reaction which occurs at the cathode during the extraction of aluminium by electrolysis.

7. M is a metal above hydrogen in the activity series and its oxide has the formula M₂O. This oxide when dissolved in water forms the corresponding hydroxide which is a good conductor of electricity. In the above context, answer the following:                 [5M]

1. What kind of combination exists between M and O?
2. How many electrons are there in the outermost shell of M?
3. Name the group to which M belongs.
4. State the reaction occurring at the cathode.
5. Name the product at the anode

Chapter 8: Hydrogen Chloride

1. For the preparation of hydrochloric acid in the laboratory:                                                                                            [2M]

1. Why is direct absorption of hydrogen chloride gas in water not feasible?
2. What arrangement is done to dissolve hydrogen chloride gas in water?

2. Identify the gas evolved and give the chemical test in each of the following cases:                                                         [2M]

1. Dilute hydrochloric acid reacts with sodium sulphite
2. Dilute hydrochloric acid reacts with iron (II) sulphide

3. The following questions pertain to the laboratory preparation of hydrogen chloride gas:                                                  [3M]

1. Write the equation for its preparation mentioning the condition required.
2. Name the drying agent used and justify your choice.
3. State a safety precaution you would take during the preparation of hydrochloric acid.

4.                                                                                                                                                                                [3M]

1. What is aqua regia?
2. State the use of aqua regia.
3. What is the function of HCl in the preparation of aqua regia?

5. Study the figure given below and answer the questions which follow:                                                                             [3M]

1. Identify gas Y.
2. What property of gas Y does this experiment demonstrate?
3. Name another gas with the same property which can be demonstrated by this experiment.

Chapter 9: Ammonia

1.                                                                                                                                                                                 [2M]

1. State why concentrated sulphuric acid is not used for drying ammonia gas.
2. Why is ammonia gas not collected over water?

2. Give balanced chemical equations for each of the following:                                                                                           [3M]

1. Laboratory preparation of ammonia using an ammonium salt
2. Reaction of ammonia with excess chlorine
3. Reaction of ammonia with sulphuric acid

3. Explain the following:                                                                                                                                                 [3M]

1. Dilute nitric acid is generally considered a typical acid but not so in its reaction with metals.
2. Concentrated nitric acid appears yellow when it is left standing in a glass bottle.
3. An all-glass apparatus is used in the laboratory preparation of nitric acid.

4. Give a balanced chemical equation for each of the following:                                                                                         [4M]

1. Action of conc. nitric acid on sulphur
2. Catalytic oxidation of ammonia
3. Laboratory preparation of nitric acid
4. Reaction of ammonia with nitric acid

5. Give reasons for the following:                                                                                                                                   [4M]

1. Liquid ammonia is used as a refrigerant in ice plants.
2. Aqueous solution of ammonia is used for removing grease stains from warm clothes.
3. Aqueous solution of ammonia gives a pungent smell.
4. Aqueous solution of ammonia conducts electricity.

Chapter 10: Nitric Acid

1.                                                                                                                                                                                [2M]

1. What is the type of salt formed when the reactants are heated at a suitable temperature for the preparation of nitric acid?
2. State why the complete apparatus is made of glass for the preparation of nitric acid.

2. Give balanced equations for the following:                                                                                                                  [2M]

1. Laboratory preparation of nitric acid
2. Preparation of ethanol from monochloroethane and aq. sodium hydroxide

3. Explain the following:                                                                                                                                                [3M]

1. Dilute nitric acid is generally considered a typical acid but not so in its reaction with metals.
2. Concentrated nitric acid appears yellow when it is left standing in a glass bottle.
3. An all-glass apparatus is used in the laboratory preparation of nitric acid.

4. Nitric acid is manufactured by Ostwald’s process.                                                                                                        [3M]

1. Give the source of ammonia gas used in the manufacture.
2. What is the ratio of ammonia to air used in the process?
3. Which metal is used as a catalyst in Ostwald’s process?

5. Name                                                                                                                                                                       [5M]

1. A solution which absorbs nitric oxide.
2. A nitrate of metal which on heating does not give nitrogen dioxide.
3. A metal nitrate which on heating is changed into metal oxide.
4. A metal nitrate which on heating is changed into metal.
5. A nitrate which on heating leaves no residue behind.

Chapter 11: Sulphuric Acid

1. Which property of sulphuric acid is shown by the reaction of concentrated sulphuric acid with                                          [2M]

1. Ethanol
2. Carbon

2.                                                                                                                                                                                 [2M]

1. Give balanced chemical equations for the action of sulphuric acid on each of the following:

1. Potassium hydrogen carbonate
2. Sulphur

3. Write balanced chemical equations to show the                                                                                                             [3M]

1. Oxidising action of conc. sulphuric acid on carbon
2. Behaviour of H2SO4 as an acid when it reacts with magnesium
3. Dehydrating property of conc. sulphuric acid with sugar

4. A, B, C and D summaries the properties of sulphuric acid depending on whether it is dilute or concentrated.                       [3M]
A = Typical acid property
B = Non-volatile acid
C = Oxidising agent
D = Dehydrating agent
Choose the property (A, B, C or D) depending on which is relevant to each of the following:

1. Preparation of hydrogen chloride gas
2. Preparation of copper sulphate from copper oxide
3. Action of conc. sulphuric acid on sulphur

5. Give one equation each to show the following properties of sulphuric acid:                                                                       [3M]

1. Dehydrating property
2. Acidic nature
3. Non-volatile acid

Chapter 12: Organic Chemistry

1. Write balanced chemical equations for the following:                                                                                                      [3M]

1. Burning of ethane in plentiful supply of air
2. Action of water on calcium carbide
3. Heating of ethanol at 170°C in the presence of conc. sulphuric acid

2. Give the structural formulae for each of the following:                                                                                                    [3M]

1. 2-methyl propane
2. 1,2 dichloroethane
3. butan-2-ol

3. Give balanced chemical equations for the following conversions:                                                                                      [3M]

1. Ethanoic acid to ethyl ethanoate
2. Acetylene to acetylene ozonide
3. Ethene to ethylene glycol

4. A compound X (having vinegar-like smell) when treated with ethanol in the presence of acid Z gives a compound Y which has a fruity smell.                                                                                                                                                                    [3M]
The reaction is

1. Identify Y and Z.
2. Write the structural formula of X.
3. Name the above reaction.

5. Identify the term or substance based on the descriptions given below:                                                                              [4M]

1. Ice-like crystals formed on cooling an organic acid sufficiently.
2. Hydrocarbon containing a triple bond used for welding purposes.
3. The property by virtue of which the compound has the same molecular formula but different structural formula.
4. 

6.                                                                                                                                                                                  [4M]

1. Define homologous series.
2. Complete the following table which relates to the homologous series of hydrocarbons.

Chapter 1: Periodic Table, Periodic Properties and Variations of Properties

1. Define the following terms:                                                                                                                                  [3M]

1. Ionisation potential
2. Electronaffinity
3. Electronegativity

2. In Period 3 of the periodic table, Element B is placed to the left of Element A. On the basis of this information, choose the correct word from the brackets to complete the following statements:                                                                                     [3M]

1. Element B would have (lower/higher) metallic character than Element A.
2. Element A would probably have (lesser/higher) electron affinity than Element B.
3. Element A would have (greater/smaller) atomic size than Element B.

3. An element has an atomic number 16.State                                                                                                            [3M]

1. the period to which it belongs
2. the number of valence electrons
3. whether it is a metal or non-metal

4. Give reasons:                                                                                                                                                      [3M]

1. The oxidising power of elements increases on moving from left to right along a period in the periodic table.
2. Ionisation potential of the element increases across a period.
3. Alkali metals are good reducing agents.

5. Use the letters only written in the periodic table given below to answer the questions that follow:                              [4M]

1. State the number of valence electrons in atom J.
2. Which element as shown forms ions with a single negative charge?
3. Which metal element is more reactive than R?
4. Which element has its electrons arranged in four shells?

6. Arrange the following as per the instructions given in the brackets:                                                                          [4M]

1. Cs, Na, Li, K, Rb (increasing order of metallic character)
2. Mg, Cl, Na, S, Si (decreasing order of atomic size)
3. Na, K, Cl, S, Si (increasing order ionisation energy)
4. Cl, F, Br, I (increasing order of electron affinity)

7. A group of elements in the periodic table is given below: (Boron is the first member of the group and thallium is the last.)
Boron, Aluminium, Gallium, Indium, Thallium Answer the following questions in relation to the above group of elements:   [5M]

1. Which element has the most metallic character?
2. Which element would be expected to have the highest electronegativity?
3. If the electronic configuration of aluminium is 2, 8, 3, how many electrons will there be in the outermost shell of thallium?
4. The atomic number of boron is 5. Write the chemical formula of the compound formed when boron reacts with chlorine.
5. Will the elements in the group to the right of this boron group be more metallic or less metallic in character? Justify your answer.

Chapter 2: Chemical Bonding

1. What is the difference between                                                                                                                               [3M]

1. Ionic compounds and polar covalent compounds
2. Ionic compounds and covalent compounds
3. Polar covalent compounds and non-polar covalent compounds

2.                                                                                                                                                                            [3M]

1. What are redox reactions?
2. Why is the reaction between manganese dioxide and hydrochloric acid a redox reaction?
3. Identify the substance oxidised and the substance reduced in the above reaction.

3.                                                                                                                                                                           [3M]

1. State the type of bonding in the following molecules:
   a) Ammonia
   b) Calcium oxide
2. Draw an electron dot diagram to show the formation of each of the following compounds:

1. Methane
2. Magnesium chloride
   [H = 1, C = 6, Mg = 12, Cl = 17]

4. Draw the orbit structure and electron dot diagrams of                                                                                            [3M]
(i) NaCl (ii) MgCl₂ (iii) CaO

Solution:

(i) Orbit structure and electron dot diagram of NaCl:

(ii) Orbit structure and electron dot diagram of MgCl2:

(iii) Orbit structure and electron dot diagram of CaO:

5. A compound has the formula H₂Y (Y= non-metal). State the following:                                                                    [4M]

1. Outer electronic configuration of Y
2. Valency of Y
3. Bonding present in H₂Y
4. Formula of the compound formed between calcium[20Ca 40 ] and Y

6. Predict the type of bonding in the following molecules:                                                                                            [5M]

1. Oxygen
2. Calcium oxide
3. Water
4. Methane
5. Ammonium ion

1. Covalent bond
2. Ionic bond
3. Covalent bond
4. Covalent bond
5. Covalent and coordinate bond

Chapter 3: Acids, Bases and Salts

1. Give balanced chemical equations for the following:                                                                                                 [3M]

1. Magnesium with Hydrochloric Acid
2. Sulphuric acid with Sodium hydroxide
3. Sodium with Sulphuric acid

2. Why don you use universal indicator, you see that solutions of different acids produce different colours. Indeed, solution of the same acid with different concentrations will also give different colours. Why?                                                                 [3M]

Solution: A universal indicator is a pH indicator made of a mixture of dyes and several compounds that shows many smooth colour changes over a wide range of pH, depending on the strength of the acid or bases. By exhibiting several colours one can determine pH of a solution ranging from 1-14. That’s also why solutions of same acid with different concentrations give different colours. The more acidic solutions turn universal indicator bright red. A less acidic solution will only turn it orange-yellow. Colour differences can be noticed in case of vinegar which is less acidic and battery acid which is more acidic.

3. Define the following as per ionic theory with examples and ionic equations wherever relevant.                                     [3M]

1. Acid
2. Base
3. Alkali

4.                                                                                                                                                                             [3M]

1. What is the pH of pure water?
2. What is the purpose of the pH scale?
3. A is a soluble acidic oxide and B is a soluble base. On comparing to the pH of water, what will be the pH of solution A and solution B?

5. You have been provided with three test tubes. One of them contains distilled water and the other two have an acidic solution and a basic solution respectively. If you are given red litmus paper, how will you identify the contents of each test tube?         [4M]

Solution: We know that bases turn red litmus to blue colour. So, when a drop from each of the test tubes is put on the red litmus paper the one which turns blue can be easily identified as a base. Then, the remaining test tubes contain either distilled water or acid. Now, the find out exactly the contents of these test tubes – a drop of basic solution is mixed with a drop of each of the remaining two solutions separately and then the nature of the drops of the mixtures is checked. If the colour of red litmus turns blue, then the second solution is neutral and if there is no change in colour, then the second solution is acidic. By the concept of neutralization, we know that acidic and basic solutions neutralize each other. Thus, we can distinguish between the three types of solutions and identify the contents of each test tube.

6. Give one example in each case:                                                                                                                              [5M]

1. A basic oxide which is soluble in water.
2. A hydroxide which is highly soluble in water.
3. A basic oxide which is insoluble in water.
4. A hydroxide which is insoluble in water.
5. A weak mineral acid.
6. A base which is not an alkali.
7. An oxide which is a base.
8. A hydrogen-containing compound which is not an acid.

7. Give one example in case-                                                                                                                                     [5M]

1. A basic oxide which is soluble in water.
2. A hydroxide which is highly soluble in water.
3. A basic oxide which is insoluble in water.
4. A hydroxide which is insoluble in water.
5. A weak mineral acid.
6. A base which is not alkali.
7. An oxide which is a base.
8. An oxide which is acid.
9. A hydrogen containing compound which is not an acid.
10. A base which does not contain a metal ion.

Solution:

1. Barium oxide (BaO)
2. Sodium hydroxide (NaOH)
3. Manganese oxide (MnO)
4. Copper hydroxide [Cu(OH)₂]
5. Carbonic acid (H₂CO₃)
6. Ferric hydroxide [Fe(OH)₃]
7. Copper oxide (CuO)
8. Carbon di oxide (CO₂)
9. Ammonia (NH₃)
10. Ammonium hydroxide (NH₄OH)

Chapter 4: Analytical Chemistry – Use of Ammonium Hydroxide and Sodium Hydroxide

1. Identify the salts P and Q from the observations below:                                                                                          [2M]

1. On performing the flame test, salt P produces a lilac-coloured flame and its solution gives a white precipitate with silver nitrate solution, which is soluble in ammonium hydroxide solution.
2. When dilute HCl is added to salt Q, a brisk effervescence is produced and the gas turns limewater milky.When NH₄OH solution is added to the above mixture (after adding dilute HCl), it produces a white precipitate which is soluble in excess NH₄OH solution.

2. State your observations when ammonium hydroxide solution is added drop by drop and in excess to each of the following solutions:                                                                                                                                                                [2M]

1. Copper sulphate solution
2. Zinc sulphate solution

3. Identify the cations in each of the following cases:                                                                                                 [3M]

1. NaOH solution when added to Solution (A) gives a reddish brown precipitate.
2. NH₄OH solution when added to Solution (B) gives a white precipitate which does not dissolve in excess.
3. NaOH solution when added to Solution (C) gives a white precipitate which is insoluble in excess.

4. Give a chemical test to distinguish between the following pairs of chemicals:                                                             [4M]

1. Lead nitrate solution and zinc nitrate solution
2. Sodium chloride solution and sodium nitrate solution
3. Ammonium hydroxide and sodium hydroxide
4. Dilute sulphuric acid and dilute hydrochloric acid

5. The following table shows the test a student performed on four aqueous solutions X, Y, Z and W. Based on the observations provided, identify the  cation present:                                                                                                                         [4M]

Solution:

1. Zn²⁺
2. Cu²⁺
3. Ca²⁺
4. NH⁴⁺

Chapter 5: Mole Concept and Stoichiometry

1. Calculate the number of gram atoms in 4.6 grams of sodium (Na = 23)                                                                  [2M]

Solution: Given:
Mass of sodium = 4.6 g
Atomic mass of Na = 23
Number of gram atom = ?

2. A gaseous hydrocarbon contains 82.76% of carbon. Given that its vapour density is 29, find its molecular formula. [C = 12, H = 11]                                                                                                                                                                      [2M]

Solution: Vapour density = 29

Empirical formula is C₂H₅.
Molecular weight = 2 × Vapour density
Molecular weight = n × (Empirical formula weight)
58 = n × (12 × 2 + 1 × 5)
n = 2
So, molecular formula = C₄H₁₀

3. Calculate the percentage of water of crystallization in CuSO₄.5H₂O
(H = 1, O = 16, S = 32, Cu = 64)                                                                                                                            [2M]

Solution: Given :
Atomic mass of H = 1
Atomic mass of O = 16
Atomic mass of S = 32
Atomic mass of Cu = 64
Molar mass of CuSO4.5H2O = (64) + (32) + (9 × 16) + (10 × 1) = 250
Molar mass of five water molecules = (10 × 1) + (5 × 16) = 90

4. A compound of X and Y has the empirical formula XY2. Its vapour density is equal to its empirical formula weight. Determine its molecular formula.                                                                                                                                                  [3M]

Solution: Given:
Empirical formula = XY₂
Vapour density = Empirical formula weight
Molecular formula = ?
Molecular weight = n(Empirical formula weight)
= 2 × V.D.
n(Empirical formula weight) = 2 × V.D.
Since, Vapour density = Empirical formula weight
n = 2
Molecular formula = 2(Empirical formula)
= 2(XY₂)
Molecular formula X₂Y₄

5. A cylinder contains 68 g of ammonia gas at STP.                                                                                                    [3M]

1. What is the volume occupied by this gas?
2. How many moles of ammonia are present in the cylinder?
3. How many molecules of ammonia are present in the cylinder?
   [N = 14, H = 1]

6. The mass of 11.2 litres of a certain gas at STP is 24 g. Find the gram molecular mass of the gas.                               [3M]

Solution: Given:
Volume of gas at STP = 11.2 litres
Mass of gas at STP = 24 g
Gram molecular mass = ?
The mass of 22.4 L of a gas at STP is equal to its gram molecular mass.
11.2 L of the gas at STP weighs 24 g
Therefore,
22.4 L of the gas will weigh

Gram molecular mass = 48 g

7. A gas cylinder can hold 1 kg of hydrogen at room temperature and pressure.                                                            [2M]

1. Find the number of moles of hydrogen present.
2. What weight of CO₂ can the cylinder hold under similar conditions of temperature and pressure? (Atomic masses: H = 1, C = 12, O = 16)

Chapter 6: Electrolysis

1. Give reasons why.                                                                                                                                               [3M]

1. Sodium chloride will conduct electricity only in the fused or aqueous solution state.
2. In the electroplating of an article with silver, the electrolyte sodium argentocyanide solution is preferred over silver nitrate solution.
3. Although copper is a good conductor of electricity, it is a non-electrolyte.

2. Three electrolytic cells A, B and C are connected in separate circuits. Electrolytic cell A contains sodium chloride solution. When the circuit is completed, a bulb in the circuit glows brightly. Electrolytic cell B contains acetic acid solution, and here, the bulb in the circuit glows dimly. The electrolytic cell C contains sugar solution, and the bulb does not glow. Give reason for each of these observations.                                                                                                                                                            [3M]

Solution:

1. Cell A contains sodium chloride solution which is a strong electrolyte and contains only ions. So, it conducts electricity and the bulb glows brightly.
2. Cell B contains both ions and molecules. So, there are few ions to conduct electricity and the bulb glows dimly.
3. Cell C contains sugar solution which is a non-electrolyte and does not contain ions. So, it is a bad conductor of electricity and the bulb does not glow.

3. State the observations at the anode and cathode during the electrolysis of                                                                  [3M]

1. Fused lead bromide using graphite electrodes
2. Copper sulphate solution using copper electrodes

4. The following questions are related to the electroplating of an article with silver:                                                           [4M]

1. Name the electrode formed by the article to be plated.
2. Which ion must be present in the article to be plated?
3. Name the electrolyte used for the electroplating of the article with silver.
4. Give the application of electrolysis.

5. Answer the following questions about the electroplating of copper wire with silver:                                                        [4M]

1. What ions must be present in the electrolyte?
2. Of what substance must the anode be made?
3. What will be made the cathode?
4. What is the equation for the reaction which takes place at the cathode?

1. Silver ions
2. Pure silver
3. Copper
4. Ag⁺ e ^- →Ag

Chapter 7: Metallurgy

1.                                                                                                                                                                               [2M]

1. Name the most common ore of the metal aluminium from which the metal is extracted. Write the chemical formula of the ore.
2. (Name the process by which the impure ore of aluminium is purified by using a concentrated solution of an alkali.

2. Answer the following questions                                                                                                                                  [2M]

1. Give the balanced equation for the reaction between iron oxide (III) and carbon monoxide.
2. Explain why powdered coke is sprinkled over the electrolytic mixture.

3. For each of the substances listed below, describe the role played in the extraction of aluminium.                                    [3M]

1. Cryolite
2. Sodium hydroxide
3. Graphite 

4.                                                                                                                                                                               [5M]

1. Give the name and formula of the ore of zinc.
2. Write equations for the following steps in the extraction of zinc:
   i. Roasting of ore
   ii. Reduction of zinc compound which is the product of the above reaction.
3. What is add into the blast furnace in addition to zinc compound?
4. State one large scale use of zinc.
5. Name the process by which zinc is purified.

5. Name the following:                                                                                                                                                [4M]

1. Process of coating of iron with zinc.
2. Alloy of lead and tin which is used in electrical circuits.
3. Ore of zinc containing its sulphide.
4. Metal oxide which can be reduced by hydrogen.

6.                                                                                                                                                                               [4M]

1. Name the solution used to react with bauxite as a first step in obtaining pure aluminium oxide in Bayer’s process.
2. Write the equation for the reaction where aluminium oxide for the electrolytic extraction of aluminium is obtained by heating aluminium hydroxide.
3. Name the compound added to pure alumina to lower the fusion temperature during the electrolytic reduction of alumina.
4. Write the equation for the reaction which occurs at the cathode during the extraction of aluminium by electrolysis.

7. M is a metal above hydrogen in the activity series and its oxide has the formula M₂O. This oxide when dissolved in water forms the corresponding hydroxide which is a good conductor of electricity. In the above context, answer the following:                 [5M]

1. What kind of combination exists between M and O?
2. How many electrons are there in the outermost shell of M?
3. Name the group to which M belongs.
4. State the reaction occurring at the cathode.
5. Name the product at the anode

Chapter 8: Hydrogen Chloride

1. For the preparation of hydrochloric acid in the laboratory:                                                                                            [2M]

1. Why is direct absorption of hydrogen chloride gas in water not feasible?
2. What arrangement is done to dissolve hydrogen chloride gas in water?

2. Identify the gas evolved and give the chemical test in each of the following cases:                                                         [2M]

1. Dilute hydrochloric acid reacts with sodium sulphite
2. Dilute hydrochloric acid reacts with iron (II) sulphide

3. The following questions pertain to the laboratory preparation of hydrogen chloride gas:                                                  [3M]

1. Write the equation for its preparation mentioning the condition required.
2. Name the drying agent used and justify your choice.
3. State a safety precaution you would take during the preparation of hydrochloric acid.

4.                                                                                                                                                                                [3M]

1. What is aqua regia?
2. State the use of aqua regia.
3. What is the function of HCl in the preparation of aqua regia?

5. Study the figure given below and answer the questions which follow:                                                                             [3M]

1. Identify gas Y.
2. What property of gas Y does this experiment demonstrate?
3. Name another gas with the same property which can be demonstrated by this experiment.

1. The gas is HCl (hydrogen chloride).
2. The ztreme solubility of hydrogen chloride gas is demonstrated by the fountain experiment.
3. Another gas which has the same property and can be demonstrated through this experiment is ammonia gas.

Chapter 9: Ammonia

1.                                                                                                                                                                                 [2M]

1. State why concentrated sulphuric acid is not used for drying ammonia gas.
2. Why is ammonia gas not collected over water?

2. Give balanced chemical equations for each of the following:                                                                                           [3M]

1. Laboratory preparation of ammonia using an ammonium salt
2. Reaction of ammonia with excess chlorine
3. Reaction of ammonia with sulphuric acid

3. Explain the following:                                                                                                                                                 [3M]

1. Dilute nitric acid is generally considered a typical acid but not so in its reaction with metals.
2. Concentrated nitric acid appears yellow when it is left standing in a glass bottle.
3. An all-glass apparatus is used in the laboratory preparation of nitric acid.

4. Give a balanced chemical equation for each of the following:                                                                                         [4M]

1. Action of conc. nitric acid on sulphur
2. Catalytic oxidation of ammonia
3. Laboratory preparation of nitric acid
4. Reaction of ammonia with nitric acid

1. Liquid ammonia is used as a refrigerant in ice plants.
2. Aqueous solution of ammonia is used for removing grease stains from warm clothes.
3. Aqueous solution of ammonia gives a pungent smell.
4. Aqueous solution of ammonia conducts electricity.

Chapter 10: Nitric Acid

1.                                                                                                                                                                                [2M]

1. What is the type of salt formed when the reactants are heated at a suitable temperature for the preparation of nitric acid?
2. State why the complete apparatus is made of glass for the preparation of nitric acid.

2. Give balanced equations for the following:                                                                                                                  [2M]

1. Laboratory preparation of nitric acid
2. Preparation of ethanol from monochloroethane and aq. sodium hydroxide

3. Explain the following:                                                                                                                                                [3M]

1. Dilute nitric acid is generally considered a typical acid but not so in its reaction with metals.
2. Concentrated nitric acid appears yellow when it is left standing in a glass bottle.
3. An all-glass apparatus is used in the laboratory preparation of nitric acid.

4. Nitric acid is manufactured by Ostwald’s process.                                                                                                        [3M]

1. Give the source of ammonia gas used in the manufacture.
2. What is the ratio of ammonia to air used in the process?
3. Which metal is used as a catalyst in Ostwald’s process?

5. Name                                                                                                                                                                       [5M]

1. A solution which absorbs nitric oxide.
2. A nitrate of metal which on heating does not give nitrogen dioxide.
3. A metal nitrate which on heating is changed into metal oxide.
4. A metal nitrate which on heating is changed into metal.
5. A nitrate which on heating leaves no residue behind.

Chapter 11: Sulphuric Acid

1. Which property of sulphuric acid is shown by the reaction of concentrated sulphuric acid with                                          [2M]

1. Ethanol
2. Carbon

2.                                                                                                                                                                                 [2M]

1. Give balanced chemical equations for the action of sulphuric acid on each of the following:

1. Potassium hydrogen carbonate
2. Sulphur

3. Write balanced chemical equations to show the                                                                                                             [3M]

1. Oxidising action of conc. sulphuric acid on carbon
2. Behaviour of H2SO4 as an acid when it reacts with magnesium
3. Dehydrating property of conc. sulphuric acid with sugar

4. A, B, C and D summaries the properties of sulphuric acid depending on whether it is dilute or concentrated.                       [3M]
    A = Typical acid property
    B = Non-volatile acid
    C = Oxidising agent
   D = Dehydrating agent
    Choose the property (A, B, C or D) depending on which is relevant to each of the following:

1. Preparation of hydrogen chloride gas
2. Preparation of copper sulphate from copper oxide
3. Action of conc. sulphuric acid on sulphur

5. Give one equation each to show the following properties of sulphuric acid:                                                                       [3M]

1. Dehydrating property
2. Acidic nature
3. Non-volatile acid

(i) Dehydrating property of sulphuric acid:
H₂SO₄ has a great affinity for water, and therefore, it acts as a dehydrating agent.


(ii) Acidic nature of sulphuric acid:
It acts as a strong dibasic acid.
H₂SO4→ 2Hi⁺ + SO₄²⁻
It reacts with metals, metal oxides, metal hydroxides, carbonates etc. to form metal sulphates and hydrogen at ordinary temperature.
Mg + H₂SO₄→ MgSO₄ + H2↑
CuO + H₂SO₄→ CuSO₄ + H₂O
2NaOH + H₂SO₄→ Na₂SO₄ + 2H₂O
ZnCO₃ + H₂SO₄→ ZnSO₄ + H₂O + CO₂↑

(iii) As a non-volatile acid: It has a high boiling point, so it is used to prepare volatile acids such as HCl,
HNO₃ and acetic acid from their salts.
NaCl + H₂SO₄→ NaHSO₄ + HCl
NaNO₃ + H₂SO₄→ NaHSO₄ + HNO₃
CH₃COONa + H₂SO₄→ NaHSO₄ + CH₃COOH

Chapter 12: Organic Chemistry

1. Write balanced chemical equations for the following:                                                                                                      [3M]

1. Burning of ethane in plentiful supply of air
2. Action of water on calcium carbide
3. Heating of ethanol at 170°C in the presence of conc. sulphuric acid

2. Give the structural formulae for each of the following:                                                                                                    [3M]

1. 2-methyl propane
2. 1,2 dichloroethane
3. butan-2-ol

3. Give balanced chemical equations for the following conversions:                                                                                      [3M]

1. Ethanoic acid to ethyl ethanoate
2. Acetylene to acetylene ozonide
3. Ethene to ethylene glycol

4. A compound X (having vinegar-like smell) when treated with ethanol in the presence of acid Z gives a compound Y which has a fruity smell.                                                                                                                                                                    [3M]
The reaction is

1. Identify Y and Z.
2. Write the structural formula of X.
3. Name the above reaction.

5. Identify the term or substance based on the descriptions given below:                                                                              [4M]

1. Ice-like crystals formed on cooling an organic acid sufficiently.
2. Hydrocarbon containing a triple bond used for welding purposes.
3. The property by virtue of which the compound has the same molecular formula but different structural formula.
4. 

6.                                                                                                                                                                                  [4M]

1. Define homologous series.
2. Complete the following table which relates to the homologous series of hydrocarbons.

Solution:

1. Homologous series is a series of compounds with the same functional group and similar chemical properties in which the members of the series can be branched and unbranched.
2.