Compound A, the main supporter of life on Earth, needs a drop of sulphuric acid to give a rocket
fuel and the supporter of combustion. Compound B, with the same components of A are
colourless and kept away from sunlight, produces A and the supporter of combustion.
compound C is prepared by using diamond and the supporter of combustion. This compound
forms a precipate with slaked lime unless excess amount is passed into it.
(a) Identify A, B and C

(b) Write balanced chemical equations in each case
(c) Name the type of reaction in each case
(d) What is the colour of the precipitate left behind in the last case?

Asked by Shivani | 25th May, 2019, 06:58: AM

Expert Answer:

(a)
Compound A is water H2O.
 
Acidified water on electrolysis gives H2 which is rocket fuel and the supporter of combustion and O2 which is the main supporter of life on Earth.
 
Compound B is H2O2 which in the presence of sunlight produces O2 which is the main supporter of life on Earth.
 
Compound C is CO2 which forms a precipitate  with slaked lime unless the excess amount is passed into it.
 
(b) and (c)  Type of the reaction and chemical equations:
 
Electric decompositon reaction:
 
 2 H2O(l) → 2 H2(g) + O2(g)
 
Photochemical decomposition reaction:
 
 2 H2O2(l) → 2 H2O(g) + O2(g)
 
Precipitation reaction:
 
Ca open parentheses OH close parentheses subscript 2 space plus space CO subscript 2 space end subscript space rightwards arrow space CaCO subscript 3 space space plus space straight H subscript 2 straight O
                                         White ppt

(d) When CO2 is passed through lime water for a short duration, it turns lime water milky due to the formation of a white precipitate of calcium carbonate.

Answered by Ramandeep | 27th May, 2019, 12:31: PM