Which law states that the volume of a gas is proportional to the moles of the gas when pressure and temperature are kept constant?

Avogadro's Law states that volume is directly proportional to the oles of the gas.

Explanation: Expression fro ideal gas equation:

This law has arrived from the combination of four laws:

1) Boyle's Law: This law states that pressure is inversely proportional to the volume of the gas at constant temperature and number of moles.

    (At constant temperature and number of moles)

2) Charles' Law: This law states that volume is directly proportional to the temperature of the gas at constant pressure and number of moles.

   (At constant pressure and number of moles)

3) Gay-Lussac's Law: This law states that pressure is directly proportional to the temperature of the gas at constant volume and number of moles.

    (At constant volume and number of moles)

4) Avogadro's Law: This law states that volume is directly proportional to the number of moles of the gas at constant pressure and temperature.

  (At constant temperature and pressure)

Hence, the correct answer is Avogadro's Law.

i'm pretty sure its b i might be wrong though!