Question

When a piece of Pb is kept in a blue coloured copper sulphate solution the colour of lead changes due to the depostion of copper. What type of reaction is this?

• A. Dispalcement reaction
• B. Combination reaction
• C. Physical reaction
• D. Decomposition reaction

Answer 1

The correct option is A

Dispalcement reaction

Lead is more reactive than copper so it displaces copper from CuSO₄ solution(the element (Pb) displaces the element (Cu) from its solution). This type of reaction is called displacement reaction. The displaced copper deposits on the lead piece. Therefore there is a change in colour of lead piece.

$Pb\left(s\right)+CuS{O}_4\left(aq\right)\to PbS{O}_4\left(aq\right)+Cu\left(s\right)$

(Copper sulphate) (Lead sulphate)