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.

Assertion (A): Hydraulic washing is a method to separate impurities from the ore.

Reason (R): In Hydraulic washing, denser particles float and lighter particles settle down.

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.

Which of the following will occupy the volume 2.8 litres at S.T.P.?
(Atomic weight: C = 12, O = 16, Cl = 35.5, S = 32)

1. 2 moles of carbon dioxide
2. 7.1 g of chlorine
3. 8 g of sulphur dioxide
4. 56 g of carbon monoxide

A salt solution which gives a reddish-brown precipitate with NaOH and a white precipitate with BaCl₂ solution is:

1. CuSO₄
2. Ca(NO₃)₂
3. Fe₂(SO₄)₃
4. FeCl₃