Question

At what temperature would gas occupy 3L?

Answer 1

From the information given you cannot answer.

Explanation:

If its an ideal gas, we know that 1 mole occupies 24.3 litres at 25 degrees celcius and 1 atmosphere pressure.
You can work out the volumes occupied at other temperatures, but you need to know the amount of gas being considered. If it's 1 mole, for example, it occupies 24.3 litres at 25 celcius and 1 atm, so in order to occupy only 3 litres, assuming pressure stays constant, the temperature would need to reduce to (3/24.3) x 298 kelvin = 36.7 kelvin.

But without number of moles and pressure you cannot work it out.