Question

A 250-mL aqueous solution contains 1.56 mc025-1.jpg 10–5 g of methanol and has a density of 1.03 g/mL. What is the concentration in ppm?
A 6.1 X 10^-8 ppm
B 1.5 X 1-^-5 ppm
C 0.061 ppm
D 15 ppm

Answer 1

The right answer for the question that is being asked and shown above is that: "B 1.5 X 1-^-5 ppm." A 250-mL aqueous solution contains 1.56 mc025-1.jpg 10–5 g of methanol and has a density of 1.03 g/mL. The concentration in ppm is that 1.5 X 1-^-5 ppm

Answer 2

Answer: The correct option is C.

Explanation: ppm is used to measure the concentration of solute in a given volume of solution. ppm is basically parts per million.

Mathematically,

$ppm=\frac{\text{Mass of solute (in mg)}}{\text{Volume of solution (in L)}}$

We are given:

Mass of methanol = $1.56\times 10^{-5}g=1.56\times 10^{-2}mg$  (Conversion Factor : 1g = 1000mg)

Volume of solution = 250 mL = 0.250L   (Conversion Factor : 1L = 1000mL)

Putting values in above equation, we get:

$ppm=\frac{1.56\times 10^{-2}mg}{0.250L}$

Concentration of methanol = 0.062ppm

Hence, the correct option is C.