Air contains $70\% \, N_2, \, 20\% \, O_2$ and $1\% \, CO_2$ by volume. If the total pressure of air is $1 \, bar$,find the partial pressure of $N_2, O_2$ and $CO_2$.

• A
  $P_{N_2} = 0.70 \, bar, P_{O_2} = 0.20 \, bar, P_{CO_2} = 0.01 \, bar$
• B
  $P_{N_2} = 0.20 \, bar, P_{O_2} = 0.70 \, bar, P_{CO_2} = 0.01 \, bar$
• C
  $P_{N_2} = 0.01 \, bar, P_{O_2} = 0.20 \, bar, P_{CO_2} = 0.70 \, bar$
• D
  $P_{N_2} = 0.70 \, bar, P_{O_2} = 0.01 \, bar, P_{CO_2} = 0.20 \, bar$