Answer: 156 K
Explanation:
Combined gas law is the combination of Boyle's law, Charles's law and Gay-Lussac's law.
The combined gas equation is,

where,
= initial pressure of gas = 450 torr
= final pressure of gas = 800 torr
= initial volume of gas = 1.80 L
= final volume of gas = 
= initial temperature of gas = 
= final temperature of gas = ?
Now put all the given values in the above equation, we get:


Thus the final temperature will be 156 K