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 10^-5 ppm
c. 0.061 ppm
d. 15 ppm

Answer 1

I think the correct answer from the choices presented above is option A. A 250-mL aqueous solution contains 1.56 g of methanol and has a density of 1.03 g/ml. Its concentration in ppm is  6.1 x 10^-8 ppm. Hope this answers the question.

Answer 2

Answer: The correct option is C.

Explanation:

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

Formula used :

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

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)

Now put all the given values in above equation, we get:

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

Concentration of methanol = 0.061ppm

Hence, the correct option is C.