Assertion (A): In a solution containing equal concentration of Cu²⁺ ions and Ca²⁺ ions, Cu²⁺ ions will be discharged in preference to Ca²⁺ ions.

Reason (R): Ca²⁺ ions are placed above Cu²⁺ ions in the electrochemical series.

1. Both (A) and (R) are true, and (R) is the correct explanation of (A).
2. Both (A) and (R) are true, and (R) is not the correct explanation of (A).
3. (A) is true but (R) is false.
4. (A) is false but (R) is true.

Both (A) and (R) are true, and (R) is the correct explanation of (A).

Reason — Cu²⁺ ions will be discharged in preference to Ca²⁺ ions because Cu²⁺ ions are present lower than Ca²⁺ ions in the electrochemical series.
Elements lower in the series get discharged more easily at the cathode during electrolysis because their cations can easily gain electrons. Hence, the assertion (A) is true.
The Cu²⁺ ions will be discharged in preference to Ca²⁺ ions because Ca²⁺ ions are placed above Cu²⁺ ions in the electrochemical series. Hence, the reason (R) is true and it correctly explains assertion (A).