Question

Which statements are correct regarding copper sulphate?

• A. It reacts with $NaOH$ and glucose to give ${Cu}_{2}O$.
• B. It reacts with $KCl$ to give ${Cu}_{2}O$.
• C. It gives $CuO$ on strong heating in air.
• D. It reacts with $KI$ to give brown colouration.

Answer 1

Answer: (A), (C), (D)

The correct options are
A It reacts with $NaOH$ and glucose to give ${Cu}_{2}O$.
C It gives $CuO$ on strong heating in air.
D It reacts with $KI$ to give brown colouration.

(A) Copper(II) ion complexed with tartarate ion in basic solution is known as Fehling solution. it oxidizes glucose and themselves gets reduced to curprous oxide.
$RCHO+2C{u}^{2+}+5O{H}^{-}\to +\underset{brickredprecipitateofcuprousoxide}{C{u}_{2}O}\downarrow +3H_{2}O$
Thus option A is correct.
(B) During reaction of copper sulfate with$KCl$, ${Cu}_{2}O$ cannot be obtained. Thus option B is incorrect.
(C) On strong heating, copper sulfate forms cupric oxide.
$2CuS{O}_4\stackrel{{750}^{o}C}{\to }2CuO+2S{O}_2+O_2$. Thus option C is correct.
(D) It reacts with KI to give brown colouration du to liberation of iodine. $2CuS{O}_4+4KI\to C{u}_2{I}_2\downarrow +I_2+2K_{2}S{O}_4$.Thus option D is correct.