(a) What is van't Hoff factor? What types of values it can have if the solute molecules undergo
(i) Dissociation ?
(ii) Association ?
(b) How many mL of a 0.1 M HCl solution are required to react completely with 1 g of a mixture of `Na_(2)CO_(3)` and `NaHCO_(3)` containing equimolar amounts of both ?
(Molar mass : `Na_(2)CO_(3)=106g, NaHCO_(3)=84 g`)

Explanation

### Step-by-Step Solution

#### (a) What is van't Hoff factor?

1. **Definition**: The van't Hoff factor (i) is a measure of the effect of solute particles on colligative properties such as boiling point elevation, freezing point depression, and osmotic pressure. It is defined as the ratio of the actual number of particles in solution after dissociation or association to the number of formula units of solute initially dissolved in the solution.

\[
i = \frac{\text{actual number of particles in solution}}{\text{number of formula units initially dissolved}}
...