Question

In the following experimental setup of electrolysis of water, if P and Q are the gases collected in the test tubes enclosing the electrodes R and S, then select the option/options in which the matching is correct:

1. P - Oxygen gas, R - Anode
2. P - Hydrogen gas, R - Cathode
3. Q - Hydrogen gas, S - Cathode
4. Q - Oxygen gas, A - Anode

Options

• (i) and (ii)

• (iii) and (iv)

• (i) and (iii)

• (ii) and (iv)

Answer 1

(i) and (iii)

Explanation:

Water electrolysis produces oxygen (O₂) at the anode (+, R) and hydrogen (H₂) at the cathode (−, S). P is near R (Anode), so it collects oxygen (O₂). Q is near S (Cathode), so it collects hydrogen (H₂). 

P - Oxygen gas, R - Anode and Q - Hydrogen gas, S - Cathode