Read the statements given below:

I — Copper is a component in the alloy that is used to make medals.
II — Aluminium is used in making the alloy stainless steel.
III — Copper is a common component of both duralumin and brass.

Which of the statements are correct?

1. I & II
2. I & III
3. II & III
4. I, II & III

Sodium hydroxide can react with …………… acid to form an acid salt.

1. Nitric acid
2. Hydrochloric acid
3. Acetic acid
4. Sulphuric acid

A white precipitate is formed when dilute hydrochloric acid reacts with ‘X’. The white precipitate is soluble in excess of NH₄OH and insoluble in dilute HNO₃. Identify ‘X’.

1. AgNO₃
2. NH₄Cl
3. AgCl
4. CaCl₂

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.