Question

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

Reaction between Copper sulphate (CuSO₄) solution and Sodium hydroxide (NaOH) occurs as follows:

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

Blue precipitates of Copper hydroxide are formed as a result of double displacement reaction.

Therefore, option (a) is correct.