• question_answer A sample of ${{O}_{2}}$ gas is collected over water at ${{23}^{o}}C$ at a barometric pressure of 751 mm Hg (vapour pressure of water at ${{23}^{o}}C$ is 21 mm Hg). The partial pressure of ${{O}_{2}}$ gas in the sample collected is       [CBSE PMT 1993] A)                 21 mm Hg            B)                 751 mm Hg C)                 0.96 atm              D)                 1.02 atm

Pressure of ${{O}_{2}}$ (dry) = 751-21 = 730 mm Hg                                 $=\frac{730}{760}=0.96atm$