Consider three metal chlorides x, y and z, where x is water soluble at room temperature, y is sparingly soluble in water at room temperature and z is soluble in hot water. x, y and z are respectively

We need to identify three metal chlorides based on their solubility properties.

x: Water soluble at room temperature

y: Sparingly soluble in water at room temperature

z: Soluble in hot water

Option 2: $$CuCl_2, AgCl, PbCl_2$$

- $$CuCl_2$$: Copper(II) chloride is readily soluble in water at room temperature. ✓ (matches x)

- $$AgCl$$: Silver chloride is sparingly soluble (nearly insoluble) in water at room temperature. ✓ (matches y)

- $$PbCl_2$$: Lead(II) chloride is sparingly soluble in cold water but dissolves readily in hot water. ✓ (matches z)

This perfectly matches all three conditions.

Checking other options:

- Option 1: $$AlCl_3$$ is soluble, $$AgCl$$ is sparingly soluble, but $$AlCl_3$$ doesn't specifically need hot water to dissolve.

- Option 3: $$BaCl_2$$ is freely soluble in water at room temperature, not specifically requiring hot water.

- Option 4: The notation $$AlCl$$ is unusual, and $$Hg_2Cl_2$$ is insoluble even in hot water.

Therefore, the correct answer is Option 2: $$CuCl_2, AgCl, PbCl_2$$.