FRANK Solutions for Class 10 Chemistry Chapter 9 - A - Ammonia
Chapter 9A - Ammonia Exercise 219
In combined state, ammonia is found as ammonium salts mainly as ammonium chloride and ammonium sulphate.
(b) What is liquor ammonia fortis?
(ii) Liquor ammonia - It is saturated solution of ammonia in water. It is very dilute solution of ammonium hydroxide (NH4OH).
(b) A saturated solution of ammonia in water is called liquor ammonia Fortis.
(ii) How is gas collected in the gas jar?
(iii) Name the substance used for drying ammonia gas? Why cannot substances such as conc.H2SO4, anhydrous calcium chloride and phosphorus pentoxide be used for drying ammonia gas?
(i) Gas obtained by treating chlorine in excess of ammonia.
(ii) Solid obtained by passing ammonia over heated copper oxide
(iii) Products obtained by burning ammonia in oxygen.
(iv) Substance used to dry ammonia
(v) Liquid when added to metallic nitride that yield ammonia.
(vi) Indicator that turns deep pink when treated with NH4OH.
(vii) Products obtained by treating with excess chlorine.
(viii) Basic gas that is used as a refrigerant.
(ix) Solution used to remove fat grease.
(x) Salt known as ammoniac.
(xi) Salt used to clean metal surface before soldering, tinning, etc.
(xii) Ammonium salt used in explosive.
(xiii) An acidic gas which reacts with a basic gas liberating neutral gas.
(xiv) A nitride of divalent metal which reacts with hot water producing ammonia.
Chapter 9A - Ammonia Exercise 220
(b) Under what conditions do the reactants combine to form ammonia? Give a balanced equation for the reaction.
(c) In what ratio by volume, are the above reactants used.
(d) State one possible source of each reactant used in the process.
(e) What is the function of:
(i) finely divided iron
(ii) Molybdenum in the above process
(f) Mention two possible ways by which ammonia produced is removed from unchanged gases.
(i) Ammonium chloride
(ii) Ammonium nitrate
State whether each reaction is an example of thermal dissociation or thermal decomposition.
(i) A good refrigerant
(ii) A cleaning agent
(iii) As a source of hydrogen
(a) It is highly volatile
(b) It has high specific latent heat of vaporization. 1 mole (17g) of liquid ammonia vaporises by absorbing 5.7 kcals of heat from the surroundings, which is there by cooled.
(c) It easily liquefies under pressure at room temperature.
(ii) Ammonia emulsifies fats and grease. Thus it is used to clean oils, fats and body grease etc. from clothes.
(iii) Liquid hydrogen is dangerous to transport as it is highly combustible. Thus, hydrogen is converted to liquid ammonia and transported in cylinders. Later it is catalytically converted to hydrogen.
Key: Uses of ammonia
(b) Why is ammonium hydroxide used in qualitative analysis? Give two equations to justify your answer.
(b) Write an equation for the reaction to prepare one fertilizer from ammonia.
(i) The source of heat is removed after sometime in Haber's process.
(ii) Ammonium nitrate is not used in the laboratory preparation of NH3.
(iii) Ca(OH)2 is preferred over NaOH in the preparation of ammonia.
(iv) Liquid NH3 has no action on litmus, while liquor ammonia has an effect.
(v) Dry N2 and H2 must be used in the Haber's process.
(vi) A promoter is added along with the catalyst in the Haber's process.
(vii) Aqueous ammonia conducts electricity.
(viii) Ammonia cannot be collected over water.
(ix) Ammonia is present in sewage water.
(x) Ammonia solution is used in the laboratory to identify metal ions.
Chapter 9A - Ammonia Exercise 221
Give balanced reactions for the following conversions:
(i) Ammonia to nitrogen using an acidic gas.
(ii) Ammonia to nitrogen using copper oxide.
(iii) Ammonia to nitrogen using oxygen.
(iv) Ammonia to nitrogen using trichloride.
(v) Ammonia to ammonium sulphate.
(vi) Ammonia solution to an amphoteric hydroxide.
(vii) Ammonia to ammonium carbonate
(viii) Copper oxide to copper.
(i) Excess ammonia is mixed with chlorine.
(ii) Ammonia in excess is mixed with chlorine.
(iii) Filter paper dipped in colourless phenolphthalein is introduced into ammonia.
(iv) Ammonia is passed over heated lead oxide.
(v) Ammonium solution is added to ferric chloride solution.
(vi) Ammonia solution is added drop by drop and then in excess to aqueous copper sulphate solution.
(vii) Ammonia comes in contact with the eyes of a person.
(a) Is alkaline in nature
(b) Has the element hydrogen in it.
(c) Has the element nitrogen in it.
(i) Action on indicators or dry ammonia gas and aqueous ammonia
(ii) Reaction of excess ammonia with chlorine and NH3 with excess chlorine
(iii) Aqueous ferrous and ferric sulphate solution
(a) Give one use each of four different compounds of ammonia.
(b) Describe two tests to identify ammonia and ammonium ions in an aqueous solution.
(a) (i) Use of Ammonium Chloride
Used in Leclanche cell and dry cell
(ii) Use of Ammonium Sulphate
Used as a fertilizer
(iii)use of Ammonium nitrate
Used in fireworks
(i) Use of Ammonium Carbonate
Used in baking powder
(b) Test of ammonia and ammonium ions:
(i) Ammonia gas has a characteristic pungent smell
(ii) A glass rod dipped in concentrated hydrochloric acid and is introduced into the gas produces thick white fumes of ammonium chloride.
What are chlorofluorocarbons, why they become popular as substitute of ammonia as refrigerant?
A chlorofluorocarbon (CFC) is an organic compound which contains carbon, chlorine and fluorine produced as a volatile derivative of methane and ethane.
Pure ammonia gas is highly toxic to humans and would pose a threat if the refrigerator were to leak. Hence, CFCs became popular as a substitute of ammonia as a refrigerant.
Give two examples of suitable alternatives of CFCs which can be used as refrigerant and are non-ozone deflecting?
(i) Hydrochlorofluorocarbon (CF3CHCl2)
(ii) Hyrofluorocarbon (HFC)
Chapter 9A - Ammonia Exercise 222
Choose the correct answer from the options given below :
(i) Ammonia is produced when ammonium chloride is heated with
(a) Potassium nitrate
(b) Slacked lime
(c) Quick lime
(d) Sodium nitrate
(ii) Ammonia reacts with excess chlorine to form
(iii) Nessler's reagent is an alkaline solution of
(d) NH2HgO HgI
(iv) Ammonia is commercially prepared by
(a) Haber's process
(b) Ostwald process
(c) Contact process
(d) Head chamber process
(v) The other products obtained along with water where NH3 is passed over heated CuO are
(a) Cu(NH2)2 and H2
(b) [Cu(NH3)4]2+ and O2
(c) Cu and N2
(d) None of these
(vi) Liquid ammonia is used in refrigeration because of its
(a) High dipole moment
(d) High heat of vaporization
(vii) In the Haber's process for the manufacture of NH3, iron is used as catalyst and molybedenum as promoter. The function of promoter is
(a) To Increase the rate of combination of gases
(b) To raise the activation energy of the reaction
(c) To increase the activity of the catalyst
(d) To increase the yield of ammonia.
(i) Slacked lime
(ii) NCl3, HCl
(iv) Cu and N2
(v) Haber's process
(vi) High heat of vaporisation
(vii) To increase the activity of the catalyst
Ammonia, sulphur dioxide, hydrogen chloride, carbon dioxide
Ammonia forms weakly basic solution when dissolved in water.
The others give acidic solution when dissolved in water.
(ii) It is used in the industrial preparation of nitric acid by Ostwald's process.
Chapter 9A - Ammonia Exercise 223
1. It is a pungent smell gas.
2. It gives white precipitate when bubbles through a solution of lead nitrate.
3. It gives a brown colour or precipitate when treated with Nessler's reagent.
Ammonia is collected in an inverted dry gas jar by the downward displacement of air.
Gaseous inputs in Haber's process are dry nitrogen and dry hydrogen gas. They are mixed in the ratio of 1:3 by volume.
The following conditions favour maximum yield of ammonia:
(a) Low temperature
(b) High pressure
(c) Use of catalyst
The gases after reaction pass through condensing pipes of cooling chamber where ammonia gets liquefied and is collected in receiver.
Ammonia can also be collected by downward displacement of air.
(i) Burning of ammonia in oxygen
(ii) Catalytic oxidation of ammonia
(iii) (a) Name the catalyst used in 1(ii)
(b) In the reaction referred to in 1(ii), the catalyst glows red hot. Why?
(c) What is the name of the industrial process which starts with the reaction reffered to in 1 (ii)?
Chapter 9A - Ammonia Exercise 224
(ii) Give two reasons to show that the solution of ammonia in water contains hydroxyl ions.
(iii) Name a simple method you would employ to prepare ammonium salts in your laboratory.
(i) Write balanced equation for the direct combination of nitrogen and hydrogen.
(ii) Which of the metals - iron, platinum, copper - catalyse this direct combination?
(iii) Is the formation of ammonia promoted by high pressure or low pressure?
(i) Heating ammonium chloride with sodium hydroxide produces ______ (ammonia, nitrogen).
(ii) Heating solution of ammonium chloride with sodium nitrite produces ______(ammonia, nitrogen).
(i) The preparation of ammonia from ammonium chloride and calcium hydroxide.
(ii) The reaction of hydrogen chloride with ammonia.
Aqueous solution of ammonia is weakly basic in nature due to presence of hydroxyl ion.
Chapter 9A - Ammonia Exercise 225
Write the equation for the formation of ammonia by the action of water on magnesium nitride.
Why is ammonia not collected over water?
Ammonia is highly soluble in water and so it is not collected over water.
(i) Write the equation for the reaction in the Haber process, that forms ammonia.
(ii) State the purpose of liquefying ammonia produced in the process.
(ii) Name the other ion formed when ammonia dissolves in water.
(iii) Give one test that can be used to detect the presence of the ion produced in (i) and (ii).
(i) A mixture of ammonium chloride and slaked lime is heated.
(ii) Aluminium nitride and water.
(b) Write an equation to illustrate the reducing nature of ammonia.
(c) With reference to Haber's process for the preparation of ammonia, write the equation and the conditions required.
(i) A metal oxide
(ii) A gas which is not oxygen
Chapter 9A - Ammonia Exercise 226
Ammonia can be obtained by adding water to:
(a) Ammonium chloride
(b) Ammonium nitrite
(c) Magnesium nitride
(d) Magnesium nitrate
Write the equation for the following :
Ammonium chloride is treated with sodium hydroxide.
State your observation for the following cases
(i) Ammonia gas is burnt in an atomosphere of oxygen in the absence of a catalyst
(ii) Glass rod dipped in ammonium hydroxide is brought near the mouth of the concentrated hydrochloric acid bottle
(i) Ammonia burns with a yellowish flame. It produces water vapour and nitrogen.
(ii) When ammonium hydroxide is brought near the mouth of concentrated hydrochloric acid, it produces dense white fumes of ammonium chloride.
The questions below are related to the manufacture of ammonia.
(i) Name the process
(ii) In what ratio must the reactants be taken
(iii) Name the catalyst used
(iv) Give the equation for the manufacture of ammonia
(v) Ammonia can act as a reducing agent write a relevant equation for such a reaction.
(i) Haber's process
(ii) 1 part of nitrogen and 3 parts of hydrogen
(iii) Finely divided iron (Fe)
The diagram shows a simple arrangement of the fountain experiment:
(i) Name the two gases you have studied which can be used in this experiment
(ii) What is the common properly demonstrated by this experiment
(i) Ammonia and hydrogen chloride gas
(ii) High solubility of gases in water
Chapter 9A - Ammonia Exercise 227
The diagram shows an experimental set-up for the laboratory prepration of a pungent smelling gas. The gas is alkaline in nature.
(i) Nature the gas collected in the jar.
(ii) Write the balance equation for the above preparation.
(iii) How is the gas being collected?
(iv) Name the drying agent used.
(v) How will you find that the jar is full of gas?
(iii) By downward displacement of air
(v) Bring moist red litmus paper to the mouth of the inverted jar; it immediately turns blue.
Bring a glass rod dipped in hydrochloric acid to the
mouth of the inverted jar. If it produces dense white
fumes, then the jar is full of gas.
Copy and complete the following table relating to important industrial process.
Name of the process
Equation for the catalyzed reaction
Name of the process
Equation for the catalyzed reaction
Finely divided iron (Fe)
Give balanced equation of
(a) Reduction of hot copper (II) oxide to copper using ammonia gas
(b) Action of heat an a mixture of copper an nitric acid
(b) C + 4HNO3→ CO2 + 2H2O + 4NO2
(i) Name the other ion formed when ammonia dissolves in water
(ii) Given one test can be used to detect the presence of the ion produced
(i) Hydroxyl (OH-) ion other than ammonium ion
(ii) Red litmus turns blue, methyl orange turns yellow and phenolphthalein turns pink.
Give balanced chemical equations for each of the following :
(i) Lab preparation of ammonia using an ammonium salt
(ii) Reaction of ammonia with excess chlorine
(iii) Reaction of ammonia with sulphuric acid
(i) 2NH4Cl + Ca(OH)2→ CaCl2 + 2H2O + 2NH3
(ii) NH3 + 3Cl2→ NCl3 + 3HCl
(iii) 2NH3+H2SO4→ (NH4)2SO4
Chapter 9A - Ammonia Exercise 228
Name the gas evolved when the following mixtures are heated:
(i) Calcium hydroxide and ammonium chloride
(ii) Sodium nitrate and ammonium chloride
Write balanced chemical equations for each of the following
(i) When excess of ammonia is treated with chlorine
(ii) An equation to illustrate the reducing nature of ammonia
(i) 8NH3 + 3Cl2→ N2 + 6NH4Cl
(ii) 3PbO + 2NH3 →3Pb + 3H2O + N2
Identify the substance underlined, in the following case:
(i) Cation that does not form a precipitate with ammonium hydroxide but forms one with sodium hydroxide.
(ii) A solid formed by reaction of two gaes, one of which is acidic and the other basic in nature.
(i) Cation that does not form a precipitate with ammonium hydroxide but forms one with sodium hydroxide: Ca2+
(ii) A solid formed by a reaction of two gases, one of which is acidic and the other basic in nature: Salt
(i) Write a balanced chemical equation for reaction of ammonia with heated copper oxide
(ii) Laboratory preparation of ammonia from aammonia chloride
(iii) Catalyst oxidation of ammonia
(i) 3CuO + 3NH3→ 3Cu + 3H2O + N2↑
(ii) 2NH4Cl + Ca(OH)2 → CaCl2 + 2H2O + 2NH3↑
State one relevant observation of burning of ammonia in air.
Since ammonia is not a supporter of combustion, it extinguishes a burning splint and does not burn in air.
Certain blank spaces are left in the following table and these are labelled as A,B,C,Da and E. Identify each of then
NaCl + H2SO4
(i) A = NaHSO4 + HCl
B = upward displacement of air
(ii) C = Mg3N2 + H2O
D = quicklime
E = downward displacement of air
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