Question

Molality of pure liquid benzene $\left(C_6{H}_6\right)$ if its density $d=2gram/ml$ is:

• A. $2$ m
• B. $0.78$ m
• C. $12.8$ m
• D. $50$ m

Answer 1

The correct option is A $2$ m

$Density=2g/ml$

Let the volume be $1000ml$

$\therefore$ Mass of benzene $=2000g$

moles of benzene $=\frac{2000}{78}=25.64$

$\therefore molality=\frac{moles}{massofthesolvent\left(kg\right)}=\frac{25.64}{2}=12.82m$