Model Paper 3 — Question 16

(a) When ethylene gas is passed through bromine water, the reddish brown colour of bromine water disappears due to the formation of the colourless dibromoethane.

$\underset{\text{ ethene}}{\text{C}_2\text{H}_4} + \text{Br}_2 \xrightarrow[\text{[inert solvent]}]{\text{CCl}_4} \underset{\text{1,2, dibromooethane [ethylene bromide]}}{\text{C}_2\text{H}_4\text{Br}_2}$

(b) When silver nitrate reacts with Hydrochloric acid it gives a white precipitate of AgCl which is insoluble in nitric acid but soluble in ammonium hydroxide.

AgNO₃ + HCl ⟶ AgCl ↓ + HNO₃

(c) Barium chloride reacts with potassium sulphate to form barium sulphate (a white insoluble solid) and potassium chloride.

BaCl₂ + K₂SO₄ ⟶ BaSO₄ + 2KCl