Answer : The partial pressure of nitrogen gas in the mixture is, 9.88 atm
Explanation :
According to the Dalton's Law, the total pressure of the gas is equal to the sum of the partial pressure of individual gases.
Formula used :

where,
= total pressure of gas = 13.6 atm
= partial pressure of helium gas = 1831 torr = 2.41 atm
= partial pressure of argon gas = 997 torr = 1.31 atm
Conversion used: (1 atm = 760 torr)
= partial pressure of nitrogen gas = ?
Now put all the given values in the above formula, we get:


Thus, the partial pressure of nitrogen gas in the mixture is, 9.88 atm