`250 mL` of nitrogen gas maintained at `720 mm` pressure and `380 mL` of oxygen gas maintained at `650 mm` pressure are put together in `1 L` flask. If temperature is kept constant, what will be the final pressure of the mixture?

Explanation

`P_(N_(2))(P_(2)=(P_(1)V_(1))/(V_(2)))=(720xx250)/(1000)(1 L of flask)=180 mm`
`P_(O_(2))=(380xx650)/(1000)=247 mm`
According to Dalton's law,
`P=P_(1)+P_(2)=180+247=427 mm`