Answer : The correct option is, (A) 446 torr
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 = 0.610 atm = 463.6 torr
conversion used : (1 atm = 760 torr)
= partial pressure of hydrogen gas = ?
= partial pressure of water vapor = 18 torr
Now put all the given values is expression, we get the partial pressure of the hydrogen gas.


Therefore, the partial pressure of
gas is, 446 torr