Question

36.5% `HCl` has density has density equal to `1.20 g mL^(-1)`. The molarity `(M)` and molality `(m)`, respectively, are
A. 15.7,15.7
B. 12,12
C. 15.7,12
D. 12,15.7

Answer 1

Correct Answer - D
`M = (% "by weight" xx 10 xx d)/(Mw_(2)) = (36.5 xx 10 xx 1.2)/(36.5) = 12 M`
`m = (36.5 xx 1000)/(36.5 xx (100 - 36.5)) = (1000)/(36.5) = 15.7 m`