Ionisation potential is maximum in:

1. Alkaline earth metals
2. Halogens
3. Inert gases
4. Alkali metals

If the RMM of carbon monoxide is 28, then its vapour density is:

1. 7
2. 56
3. 14
4. 88

Assertion (A): Acetic acid has four hydrogen atoms in its molecule but its basicity is one.

Reason (R): Acetic acid has only one replaceable hydrogen atom.

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

The hydroxide which is soluble in excess of NH₄OH is:

1. Ferric hydroxide
2. Lead hydroxide
3. Copper hydroxide
4. Calcium hydroxide