Question

Density of 3 M NaOH is 1.25 g/ml. Molality of solutions is.

• A. 2.65
• B. 2.5
• C. 2.8
• D. 3

Hint:

When converting between molarity and molality, use the relationship that involves the density and molar mass.

Answer 1

The Correct Option is A

To calculate molality (\( m \)), use the formula: \[ m = \frac{M \times 1000}{1000 \times d - M \times M_w} \] where \( M \) is molarity, \( d \) is density, and \( M_w \) is the molar mass of NaOH. By substituting the given values, the molality comes out to 2.65.