<u>417 K is the “final temperature” of the gas</u>.
<u>Explanation</u>:
According to “Charles law” the change in “volume” of a given mass of gas expanded is “directly proportional” to the “temperature” of the given gas expanded. When we keep “pressure” of the gas as constant. Mathematically,


If gas is expanded from initial volume to final volume and initial temperature to final temperature then,


Given that,
Initial volume is 1.0L
Final volume is 1.5L

To find final temperature of the gas
Substitute the given values,



Therefore, <u>final temperature of the gas after expanding is 417 K</u>.