Answer:
78 mmHg is the partial pressure of the nitrogen.
Step-by-step explanation:
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 pressure of the gas mixture = 456 mmHg
= partial pressure of hydrogen gas = 230 mmHg
= partial pressure of oxygen gas = 148 mmHg
= partial pressure of nitrogen gas = ?
Now put all the given values is expression, we get the partial pressure of the nitrogen gas i.e.
.


78 mmHg is the partial pressure of the nitrogen.