Question

A 6.50 molal solution of KOH (aq.) has a density of 1.89 g cm⁻³. The molarity of the solution is ______ mol dm⁻³. (Round off to the Nearest Integer)

[Atomic masses: K: 39.0 u; O: 16.0 u; H: 1.0 u]

विकल्प

• 3

• 5

• 7

• 9

Answer 1

A 6.50 molal solution of KOH (aq.) has a density of 1.89 g cm⁻³. The molarity of the solution is 9 mol dm⁻³.

Explanation:

m = ${\displaystyle \frac{1000\times \text{M}}{(1000\times \text{d}-\text{M}\times {\text{M}}_{\text{solute}})}}$

6.5 = ${\displaystyle \frac{1000\times \text{M}}{1890-\text{M}\times 56}}$

12285 – 364 M = 1000 M

1364 M = 12285

M = 9