Question

A sample of drinking water contains 11.95 ppm of chloroform. The molality of sample is
0 10 m
0 10 7 m
0 10² m
0 10 m​

Answer 1

Correct Question:

A sample of drinking water contains 11.95 ppm of chloroform. The molality of the sample is :

(a) 10 m

(b) 10 7 m

(c) 10² m

(d) 10⁻⁴ m​

Correct Answer:

Given:

The concentration of chloroform = 11.95 ppm

To Find:

The molality of the given chloroform sample.

Calculation:

- The molar mass of chloroform = 119.5 gm/mol

- ppm concentration = (w / W) × 10⁶

⇒ 11.95 = (w / W) × 10⁶

⇒ w = 11.95 × 10⁻⁶ × W

- Molality = (w × 1000) / (M.wt × W)

⇒ m =  (11.95 × 10⁻⁶ × W × 1000) / (119.5 × W)

⇒ m = 0.1 × 10⁻³

⇒ m = 10⁻⁴ m

- So, the correct answer is (d) 10⁻⁴ m.