`{:(" Column X "," Column Y "),("a. Molarity " ," i. For very dilute solution "),("b. Molality " ," ii. No units "),("c. mole fraction "," iii. Mol L"^(–1) ),("d. ppm " ," iv. independent of temperature"):}`

Answer

To solve the problem of matching the items in Column X with those in Column Y, we will analyze each term in Column X and find its corresponding description in Column Y.

### Step-by-Step Solution:

1. **Identify Molarity (Column X: a)**
- Molarity is defined as the number of moles of solute per liter of solution.
- The unit of molarity is moles per liter (mol L⁻¹).
- Therefore, Molarity corresponds to option iii (Mol L⁻¹).

2. **Identify Molality (Column X: b)**
- Molality is defined as the number of moles of solute per kilogram of solvent.
- It is independent of temperature because it is based on mass (kg) rather than volume (L).
- Therefore, Molality corresponds to option iv (independent of temperature).

3. **Identify Mole Fraction (Column X: c)**
- Mole fraction is defined as the ratio of the number of moles of solute to the total number of moles of all components in the solution.
- Since it is a ratio, mole fraction has no units.
- Therefore, Mole Fraction corresponds to option ii (No units).

4. **Identify Parts Per Million (ppm) (Column X: d)**
- Parts per million (ppm) is commonly used for very dilute solutions to express concentration.
- Therefore, ppm corresponds to option i (For very dilute solution).

### Final Matching:
- a. Molarity → iii. Mol L⁻¹
- b. Molality → iv. independent of temperature
- c. Mole Fraction → ii. No units
- d. ppm → i. For very dilute solution

### Summary of Matches:
- a → iii
- b → iv
- c → ii
- d → i