What volume would 2.25 moles of ne gas occupy at stp?

As we know that one mole of any Ideal gas at standard temperature and pressure occupies exactly 22.4 dm³ volume.

Solution for problem:

When 1 mole Neon (Ne) occupies 22.4 dm³ at STP then the volume occupied by 2.25 moles of Neon is calculated as,

                                             = ( 22.4 dm³ × 2.25 moles ) ÷ 1 mole
                
                                             = 50.4 dm³                   1dm³ = 1 L

Result:

So, 50.4 dm³ (Liter) volume will be occupied by 2.25 moles of Neon gas if it acts ideally at STP.

The mass has escaped into a gas which you can not see so the law stays true.