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Question

When a metal X is added to an aqueous solution of copper (II) sulphate, a reddish brown solid is liberated. Which of the following is/are true?
i. The cation of X is a weaker oxidizing agent than the copper(II) ion
ii.X is a stronger reducing agent than copper
iii. The cation of X is reddish brown

A. i only
B. i and ii only
C. i and iii only
D. ii and iii only

Answer 1

The answer is B.

ii is correct. A more reactive metal (X) can displace a less reactive (copper) from the solution of a copper salt (copper(II) sulphate). A more reactive metal is a stronger reducing agent. Therefore, X is a strong reducing agent than copper.

i is correct. The strong the reducing agent is a metal, the weaker the oxidizing agent is its cation. Since X is a stronger reducing agent than copper, the cation of X is a weaker oxidizing agent than copper(II) ion.

iii is incorrect. Since X is an unknown metal, the colour of cation of X is unknown. Furthermore, the reddish brown brown solid in the question is copper metal, and such colour gives no information about the colour of the cation of X.