Areaction of 0.028 g of magnesium with excess hydrochloric acid generated 31.0 ml of hydrogen gas. the gas was collected by water displacement in a 22 °c water bath. the barometric pressure in the lab that day was 746 mm hg. use dalton's law to calculate the partial pressure of hydrogen gas in the gas-collecting tube.

Answer :  The partial pressure of is, 726.2 mmHg

Solution :

According to the Dalton's law, the total pressure of the gas is equal to the sum of the partial pressure of the mixture of gasses.

where,

= total partial pressure = barometric pressure = 746 mmHg

= partial pressure of hydrogen gas = ?

= partial pressure of water vapor = 19.8 mmHg  (assume)

Now put all the given values is expression, we get the partial pressure of the hydrogen gas.

Therefore, the partial pressure of is, 726.2 mmHg