Answer: At a temperature of 34.44 K the volume and pressure of this gas become one-third of their initial values.
Step-by-step explanation:
Given :
= 1.2 L,

= 3 atm,
,

Formula used to calculate the final temperature is as follows.

Substitute the values into above formula as follows.

Thus, we can conclude that the final temperature is 34.44 K.