What will be the molality of the solution containing 18.25 g of HCl gas in 500 g of water?

The molar mass of HCl is 1x1 + 35.5x1 = 36.5. The given solution contains 18.25g of HCl gas. The number of moles is 18.25/36.5 = 0.5 mol. The molality is calculated by the formula

Molality = 0.5/0.5 = 1m.

The molality of the solution is 1 m. The correct answer is (iv).