Answer : The pressure of hydrogen gas is 8.96 atm.
Explanation :
The given balanced chemical reaction is:

From the balanced chemical reaction we conclude that,
As, 2 moles of Al react to give 3 moles of
gas
So, 4.50 moles of Al react to give
moles of
gas
Now we have to calculate the moles of
gas when percent yield is 75.4.

Now we have to calculate the pressure of
gas.
Using ideal gas equation :
PV = nRT
where,
P = Pressure of hydrogen gas = ?
V = Volume of the hydrogen gas = 14.0 L
n = number of moles of hydrogen gas = 5.09 moles
R = Gas constant = 
T = Temperature of hydrogen gas = 300 K
Putting values in above equation, we get:

Therefore, the pressure of hydrogen gas is 8.96 atm.