Question

The reaction between Copper sulphate solution and Sodium hydroxide is a precipitation reaction. The color of the precipitate so formed is

• A. Blue.
• B. White.
• C. Yellow.
• D. Red.

Answer 1

The correct option is A

Blue.

The explanation for the correct answer

Option A

• Solution of Copper sulphate (${\mathrm{CuSO}}_4$) reacts with sodium hydroxide($\mathrm{NaOH}$) to form a blue precipitate of Copper hydroxide($\mathrm{Cu}{\left(\mathrm{OH}\right)}_2$) and Sodium sulphate(${\mathrm{Na}}_2{\mathrm{SO}}_4$).
• Chemical equation:

$\underset{\mathrm{Copper}\mathrm{sulphate}}{{\mathrm{CuSO}}_4\left(\mathrm{aq}\right)}+\underset{\mathrm{Sodium}\mathrm{hydroxide}}{2\mathrm{NaOH}\left(\mathrm{aq}\right)}\to \underset{\mathrm{Copper}\mathrm{hydroxide}}{\mathrm{Cu}{\left(\mathrm{OH}\right)}_2\left(\mathrm{s}\right)}+\underset{\mathrm{Sodium}\mathrm{sulphate}}{{\mathrm{Na}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)}$

Hence option A is correct, the reaction between Copper sulphate solution and Sodium hydroxide is a precipitation reaction. The color of the precipitate so formed is blue.