Question

1. Identify the substance oxidised, substance reduced, oxidising agent and reducing agent in the reaction:

Cl₂ + 2l^- → 2Cl^- + l₂

2. Calculate the oxidation number of underlined elements in the following compounds:

(i) K₂Cr₂O₇ 

(ii) HHO₃

Answer 1

1. Cl₂ is reduced, therefore Cl₂ is the oxidising agent. I’ is oxidised, therefore I” is the reducing agent.

(i) K₂Cr₂O₇

(+1 × 2) + 2x +(-2 × 7) = 0 

+2 + 2x – 14 =0 

2x – 12 =0 

2x = 12 

x = +6 

(ii) HHO₃ 

(+1 × 1) + x + (-2 × 3) = 0 

1+ x – 6 = 0 

x – 5 = 0 

x = +5