Answer : The pressure would have to be increased to 6.0 atm.
Explanation :
According top the Henry's Law, the solubility of a gas in a liquid is directly proportional to the pressure of the gas.
![S\propto P](https://img.qammunity.org/2021/formulas/chemistry/high-school/j2nzima72lfxdh8vmr2z3ctks75289y3qm.png)
or,
![(S_1)/(S_2)=(P_1)/(P_2)](https://img.qammunity.org/2021/formulas/chemistry/high-school/lgozmquhk7pje4va18f4dsen1k3sjv8kkd.png)
where,
= initial solubility of gas = 0.85 g/mL
= final solubility of gas = 5.1 g/mL
= initial pressure of gas = 1.0 atm
= final pressure of gas = ?
Now put all the given values in the above formula, we get the final pressure of the gas.
![(0.85g/mL)/(5.1g/mL)=(1.0atm)/(P_2)](https://img.qammunity.org/2021/formulas/chemistry/high-school/cl6hsr57qz9cqd5eun9xk2pa859vi2jej8.png)
![P_2=6.0atm](https://img.qammunity.org/2021/formulas/chemistry/high-school/cgrjqlqil7gcdkmuhegcy909zemy2zi39q.png)
Therefore, the pressure would have to be increased to 6.0 atm.