Question

10.What will be the molality of the solution containing 18.25 g of HCl gas in 500 g of water? (Atomic mass of H = 1u and Cl =35.5u)

Answer 1

Answer:

1 molal

Explanation:

Answer 2

1 m

Given:

Atomic mass of Hydrogen = 1 u

Atomic Mass of Chlorine = 35.5 u

Weight of HCl gas = 18.25 grams

Weight of water = 500 grams

Converting weight of water in kilograms by dividing by 1000:

= 500 / 1000

= 0.5

To Find:

Molality of the solution

Formula used to find the molality of a solution:

Molality = No of moles of solute / mass of solvent in kg

Calculating Molar Mass of HCl:

= 1 x 35.5 + 1 x 1

= 35.5 + 1

= 36.5

Calculating number of moles :

= Weight of HCl / Molar mass of HCl

Substituting the values known to us in this formula we get:

= 18.25 / 36.5

= 0.5

Calculating Molality of the solution:

No of moles of HCl / mass of Water in kg

= 0.5 / 0.5

= 1 m

Therefore, the molality of the solution is 1 m.