JAMB - Chemistry (2024 - No. 52)
Concentrated sodium chloride solution is electrolyzed using mercury cathode and graphite anode. The products at the anode and the cathode respectively are
hydrogen and chlorine
chlorine and hydrogen
chlorine and sodium
sodium and chlorine
설명
When a concentrated sodium chloride solution is electrolyzed using a mercury cathode and graphite anode, the products are hydrogen gas at the cathode and chlorine gas at the anode
At the anode, 2Cl\(^-\) → Cl\(_2\) + 2e\(^-\)
At the cathode, 2H\(^+\) + 2e\(^-\) → H\(_2\)
During the electrolysis, hydrogen and chloride ions are removed from solution whereas sodium and hydroxide ions are left behind in solution. This means that sodium hydroxide is also formed during the electrolysis of sodium chloride solution.