BITSAT2019Chemistrys Block ElementsActual
Which of the following salt would give SO 2 with hot and dil H 2 SO 4 and also decolourises Br 2 water?
Options
- ANa 2 SO 3
- BNaHSO 4
- CNa 2 SO 4
- DNa 2   S
Correct answer
A. Na 2 SO 3
Step-by-step solution
When Na 2 SO 3 reacts with hot and dil H 2 SO 4 , it gives SO 2 g which decolourises bromine-water. The reaction proceed as follows: (i) Na 2 SO 3 + H 2 SO 4 ⟶ Na 2 SO 4 + SO 2 + H 2 O (ii) Br 2 + H 2 O ⟶ 2 HBr + O (iii) SO 2 + O ⟶ SO 3 (decolourisation of bromine-water)