At stp, 4 liters of o2 contains the same total number of molecules as
(1) 1 l of nh3 (3) 8 l of he
(2) 2 l of cl2 (4) 4 l of co2

The answer is (4) 4 L of CO2. For gas, the ratio of volume and mole number is the same under same pressure and temperature. So the molecule number is also the same. Then the answer should be the same volume gas.

B"hf and f-"  is the correct answer took the test on edgenuity and got it right