Question

A reference solution is to be prepared with 5 PPM parabenzopyrene (molecular weight = 252). The quantity of parabenzopyrene required for preparing one litre 5 PPM solution is
(A) 252 mg (B) 25.2 mg (C) 5 mg (D) 252 g

Answer 1

You want 5 ppm. Remembering that 1 ppm is 1 mg/L, you want 5 mg/L.
So if you want 5 ppm that is 5 mg/L; you want 1 L which means you want 5 mg. Right?

Answer 2

5 mg