Question

What happens when (give chemical equations only): (i) Concentrated H\(_2\)SO\(_4\) is added in calcium fluoride?
(ii) SO\(_3\) is passed in water?
(iii) Calcium hydroxide reacts with ammonium chloride?
(iv) Concentrated sulphuric acid and copper metal is heated?
(v) Chlorine gas is passed in cold caustic soda solution?

Hint:

In many reactions with sulfuric acid, it acts as a dehydrating agent, while chlorine and sodium hydroxide react to form bleaching powder (NaOCl).

Answer 1

(i) Concentrated H\(_2\)SO\(_4\) is added in calcium fluoride:
When concentrated sulfuric acid is added to calcium fluoride, it reacts to form calcium bisulfate and hydrogen fluoride gas: \[ \text{CaF}_2 (s) + \text{H}_2\text{SO}_4 (aq) \rightarrow \text{Ca(HSO}_4)_2 (aq) + \text{HF (g)} \]
(ii) SO\(_3\) is passed in water:
Sulfur trioxide reacts with water to form sulfuric acid: \[ \text{SO}_3 (g) + \text{H}_2\text{O} (l) \rightarrow \text{H}_2\text{SO}_4 (aq) \]
(iii) Calcium hydroxide reacts with ammonium chloride:
Calcium hydroxide reacts with ammonium chloride to form calcium chloride, water, and ammonia gas: \[ \text{Ca(OH)}_2 (aq) + 2 \text{NH}_4\text{Cl} (aq) \rightarrow \text{CaCl}_2 (aq) + 2 \text{NH}_3 (g) + \text{H}_2\text{O} (l) \]
(iv) Concentrated sulphuric acid and copper metal is heated:
When concentrated sulfuric acid reacts with copper metal, it forms copper(II) sulfate and sulfur dioxide gas: \[ \text{Cu (s)} + 2 \text{H}_2\text{SO}_4 (aq) \rightarrow \text{CuSO}_4 (aq) + \text{SO}_2 (g) + 2 \text{H}_2\text{O} (l) \]
(v) Chlorine gas is passed in cold caustic soda solution:
When chlorine gas is passed through cold caustic soda (sodium hydroxide), it forms sodium chloride and sodium hypochlorite: \[ \text{Cl}_2 (g) + 2 \text{NaOH} (aq) \rightarrow \text{NaCl} (aq) + \text{NaOCl} (aq) + \text{H}_2\text{O} (l) \]