According to Avogadro's law, as the number of moles of gas increases, what happens to its volume?

Avogadro Law gives the relationship between volume and amount when pressure and temperature are held constant. Remember amount is measured in moles. Also, since volume is one of the variables, that means the container holding the gas is flexible in some way and can expand or contract.

If the amount of gas in a container is increased, the volume increases.

If the amount of gas in a container is decreased, the volume decreases.

Suppose the amount of gas is increased. This means there are more gas molecules and this will increase the number of impacts on the container walls. This means the gas pressure inside the container will increase (for an instant), becoming greater than the pressure on the outside of the walls. This causes the walls to move outward. In this process the volume of gas has increased.

Suppose the amount is decreased. This means there are less gas molecules and this will decrease the number of impacts on the container walls. This means the gas pressure inside the container will decrease (for an instant), becoming lesser than the pressure on the outside of the walls. This causes the walls to move inward. In this process the volume of gas will decrease.

The mathematical form of Avogadro's Law is: V ÷ n = k

Volume taken up by gas at fixed pressure and temperature directly depends on its number of moles. The greater are the number of moles of a gas , the higher will be its volume and vice versa.