Match the following:

A-ii, B-iii, C-i, D-iv

The correct answer is option 1. A-ii, B-iii, C-i, D-iv.

Let us delve deeper into each term:

A. Molality: Molality (m) is a measure of the concentration of a solution expressed as the number of moles of solute per kilogram of solvent. It is calculated using the formula:

\[ \text{Molality (m)} = \frac{\text{Number of moles of solute}}{\text{Mass of solvent (in kilograms)}} \]

B. Molarity: Molarity (M) is another measure of the concentration of a solution expressed as the number of moles of solute per liter of solution. It is calculated using the formula:

\[ \text{Molarity (M)} = \frac{\text{Number of moles of solute}}{\text{Volume of solution (in liters)}} \]

C. Normality: Normality (N) is a measure of the concentration of a solution based on the number of equivalents of solute present in one liter of solution. It is particularly useful in acid-base reactions and other reactions involving equivalents. The formula for normality depends on the type of reaction being considered.

D. Mole fraction: Mole fraction \((\chi)\) is a dimensionless quantity that expresses the ratio of the number of moles of one component of a solution to the total number of moles of all components present in the solution. It is calculated using the formula:

\[ \text{Mole fraction }(\chi ) = \frac{\text{Number of moles of solute (or solvent)}}{\text{Total number of moles of all components in solution}} \]

These concepts are fundamental in understanding the composition and properties of solutions in chemistry. Each measure provides unique insights into the concentration and behavior of solutes in a solvent, and they are applicable in various experimental and theoretical contexts.