A sample of drinking water severely contaminated with chloroform, `CHCI_3` is supposed to be carcinogenic in nature. The level of contamination was 15 ppm (by mass). What is the molality of chloroform in the water sample?

Options

A. `2.25 xx 10^(-5)m`
B. `1.25 xx 10^(-4) m`
C. `1.85 xx 10^(-6) m`
D. `1.72 xx 10^(-5) m`

Answer

B

Explanation

15 ppm means 15 g of `CHCl_3` are dissolved in `10^6` g of solvent.
Molality = `(w_B//m_B)/("Mass of solvent")xx1000`
`w_B = 15 g, mg= 119.5, M_B = 10^6 g`
Molality `= (15//119.5)/(10^6)xx1000 = 1.25 xx 10^(-4) m`