Question

what happens when (a)solid sodlum hydrogen carbonate is heated (b) chlorine gas is passed through dry slaked lime (c) gypsum is heated to a temperature of 373k

Answer 1

Answer: a) Sodium carbonate, carbon dioxide and water are produced.

b) Bleaching powder is produced.

c) Plaster of Paris is formed.

Explanation:

a) When Sodium hydrogen carbonate is heated, it produces sodium carbonate, carbon dioxide and water. This released carbon dioxide is used in the fire extinguishers.

$2NaHCO_3(s)\overset{\Delta }{\rightarrow}CO_2(g)+Na_2CO_3(s)+H_2O(l)$

b) When chlorine gas is passed through dry slaked lime, it produces bleaching powder and water.

$Ca(OH)_2(s)+Cl_2(g)\rightarrow CaOCl_2(s)+H_2O(l)$

c) When gypsum (calcium sulfate dihydrate) is heated at 373 K, the products are calcium sulfate hemihydrate or commonly known as Plaster of Paris.

$CaSO_4.2H_2O(s)\overset{373K}{\rightarrow}CaSO_4.\frac{1}{2}H_2O(s)$

Answer 2

(a) When Solid sodium hydrogen carbonate is heated from sodium chloride Na2CO3.10H2O (washing soda).

2NaHCO3 ——–Heat———-> Na2CO3 +H2O+CO2

(b) when Chlorine gas is passed through dry slaked lime, Bleaching powder is produced. Bleaching powder is represented as CaOCl2, though the actual composition is quite complex.

Ca(OH)2 + Cl2 → CaOCl2 + H2O

(c) if Gypsum is heated to a temperature of 373 K. It forms plaster of Paris,

CaSO4 ½ H2O CaSO4 2H2O — -373 K ——> CaSO4 ½ H2O + 3/2 H2O

Hope it helps u .....