For an ideal gas, which two variables are directly proportional to each other (if all other conditions remain constant)?
1. T and n
2. V and n
3. V and T

3. V and T

Explanation:

For an ideal gas the volume and temperature remains directly proportional even if other conditions are constant.

This is the premise of the Charles's law.

Charles's law propounded by Jacques Charles found the relationship between the volume and temperature under constant pressure and predicted the absolute scale of temperature.

His law states that;

         "The volume of a fixed mass (mole) of a gas varies directly as its absolute temperature if the pressure is constant".

So;

                  V ∝ T (P, n constant)