Question

The relative humidity of air is $\text{80\%}$ at $\text{27} \,{}^{\text{o}} \text{C} \text{.}$ .If the aqueous tension at the same temperature is $\text{27} \, \text{mm}$ of $\text{Hg} \text{.}$ The partial pressure of water vapour in the air will be (in $\text{mm}$ of $\text{Hg}$ ).

Answer 1

Relative humidity $=\frac{P a r t i a l \, p r e s s u r e}{V a p o u r \, p r e s s u r e}\times 100$

$\Rightarrow \frac{P a r t i a l \, p r e s s u r e}{27}\times 100=80$

$\Rightarrow Partial \, pressure=\frac{80 \times 27}{100}$

$\therefore Partial \, pressure=21.6 \, mm$ of Hg