Chemical Changes and Reactions — Question 5

(a) A photochemical reaction involving 1. silver salt
2AgNO₃ $\xrightarrow{\text{sunlight}}$ 2Ag + 2NO₂ ↑ + O₂ ↑ 2. water
Cl₂ + H₂O $\xrightarrow{\text{sunlight}}$ HCl + HClO

(b) A reaction involving 1. blue solution

$\underset{\text{ iron}}{\text{Fe}} + \underset{\text{ blue sol.}}{\text{CuSO}_4} \longrightarrow \underset{\text{ green sol.}}{\text{FeSO}_4} + \underset{\text{ copper-brown red deposit}}{\text{Cu}}$

2. formation of a dirty green precipitate

$\underset{\text{ ferrous sulphate}}{\text{FeSO}_4} + \underset{\text{ sodium hydroxide}}{2\text{NaOH}} \longrightarrow \underset{\text{ dirty green ppt. }}{\text{Fe(OH)}_2}↓ + \underset{\text{ sodium sulphate}}{\text{Na}_2\text{SO}_4}$

(c) Two gases combine to form a white solid.

NH₃ (g) + HCl (g) ⟶ NH₄Cl (s)

(d) Two solids combine to form a liquid.

C (s) + 2S (s) ⟶ CS₂ (l)

(e) A reaction where color change is noticed.

$\underset{\text{ iron}}{\text{Fe}} + \underset{\text{ blue sol.}}{\text{CuSO}_4} \text{ (aq.)} \longrightarrow \underset{\text{ green sol.}}{\text{FeSO}_4} + \underset{\text{ copper-brown red deposit}}{\text{Cu}}$