AP EAPCET 15th May 2023 Shift 1 Solved Paper

A 100L cylinder containing H2 exerted a pressure of 4‌atm at 300K. It was accidentally opened and some H2 was escaped. When it was closed, it exerted a pressure of 3‌atm at 300K. The number of moles of H2 remaining in the cylinder is equal to
(Assume H2 as an ideal gas; R= gas constant)