Question

Q5. Two compounds of calcium, one 'A' being hydrated when heated forms another
hydrated compound 'X' which is used by doctors as plaster Second compound 'B' on
treating with a greenish-yellow gas 'G' a byproduct of chlor-alkali process, forms 'Y'
which is used in disinfection of water
(1)Identify 'A', 'B','G','X','Y'.​

Answer 1

Explanation:

Given -

1. 'A' being hydrated when heated forms another hydrated compound 'X'.
2. X is used as plaster.
3. 'B' on treating with a greenish-yellow gas 'G' a byproduct of chlor-alkali process, forms 'Y'.
4. Y is used in disinfection of water.

To Find -

• Identify A, B, G, X, Y

Now,

As we know that :-

1. CaSO4.½H2O is used as plaster for setting fractured bones.

When we heat Gypsum then it decomposes into plaster of paris and water.

Chemical equation :-

• CaSO4.2H2O → CaSO4.½H2O + ³/²H2O

Note :-

• The temperature during heating of gypsum shouldn't be allow to go above 100°C because if Gypsum is heated above 100°C then it forms dead burnt plaster.

Hence,

Compound A is CaSO4.2H2O (Gypsum)

and Compound X is CaSO4. ½H2O (P.O.P)

As we know that :-

1. Bleaching powder is used in disinfection of water.
2. Chlorine gas (G) is byproduct of Chlor-alkali process.

It means,

• B + Cl2 → CaOCl2

we know that,

When we treat calcium hydroxide with chlorine then it forms calcium oxychloride (Bleaching powder).

Chemical equation :-

• Ca(OH)2 + Cl2 → CaOCl2 + H2O

Hence,

Compound B is Ca(OH)2

Gas G is Cl2

Compound Y is CaOCl2.