One of the forms of a naturally occurring solid compound `P` is usually used for making the floors of houses. On adding a few drops of dilute hydrochloric acid to `P`, brisk effervescence are produced. When `50 g` of reactant `P` was heated strongly, than `22 g` of a gas `Q` and `28 g` of a solid `R` were produced as products. Gas `Q` is said to cause global warning whereas solid `R` is used for white-washing.
(a) What is (i) solid `P` (ii) gas `Q`, and (iii) solid `R`.
(b) What is the total mass of `Q` and `R` obtained from `50` g of `P` ?
(c) How does the total mass of `Q` and `R` formed compare with the mass of `P` taken ?
(d) What conclusion do you get from the comparison of masses of products and reactant ?
(e) Which law of chemical combination is illustrated by the example given in this problem ?

Explanation

(a) (i) Calcium carbonate `(CaCO_(3))` in the form of marble (ii) Carbon dioxide `(CO_(2))` (iii) Calcium oxide `(CaO)` (b) `50 g` (c ) Total mass of Q and R `(50 g)` is euqal to the mass of P taken `(50 g)` (d) The mass of products is equal to the mass of reactant (e ) Law of conservation of mass