An iron nail dipped in copper sulphate solution turns brown. This is d

An iron nail dipped in copper sulphate solution turns brown. This is due to which one of the following types of reactions ?

[amp_mcq option1=”Addition reaction” option2=”Decomposition reaction” option3=”Substitution reaction” option4=”Displacement reaction” correct=”option4″]

This question was previously asked in

UPSC NDA-1 – 2023

Download PDF Attempt Online

The correct answer is D) Displacement reaction.

This reaction involves a more reactive metal (iron, Fe) displacing a less reactive metal (copper, Cu) from its salt solution (copper sulphate, CuSO4). The general form of a displacement reaction involving metals is A + BX → AX + B, where A is more reactive than B.

The reaction is represented as: Fe(s) + CuSO4(aq) → FeSO4(aq) + Cu(s). The iron nail gets coated with brown copper metal. This is a classic example illustrating the reactivity series of metals, where iron is higher than copper. It is also a redox reaction where iron is oxidized and copper ions are reduced. While substitution reactions also involve replacement, “displacement reaction” is the specific term used for this type of reaction involving elements and compounds.

More similar MCQ questions for Exam preparation:-