$\therefore \mathrm{X}_{\mathrm{gas}}=0.98$
$\mathrm{P}_{\text {total }}=1.2 \mathrm{atm}$
partial pressure of dry-air $=\mathrm{P}_{\mathrm{T}} \times$ mole fraction of dry-air
Partial pressure of dry-air $=1.2\; atm \times 0.98 =1.176\; \mathrm{atm}$