The density of liquid (mol.wt. `= 70`) is `1.2 g mL^(-1)`. If `2 mL` of liquid contains `35` drops, the number of molecules of liquid in one drop are:

Options

A. `((1.2)/(35))N_(A)`
B. `(1)/(1.2)((1)/(35))^(2)N_(A)`
C. `(1.2)/((35)^(2))N_(A)`
D. `1.2N_(A)`

Answer

3

Explanation

Mass of one drop `=(2)/(35)xx1.2=(2.4)/(35)g`
Moles of liquid in one drop `=(2.4)/(35xx70)=(1.2)/(35^(2))`
`:. ` Molecules `=(1.2)/(35^(2))xxN_(A)`