In which of the following reactions, the equilibrium remains unaffected on addition of small amount of argon at constant volume?
1
H2 (g) + I2 (g) \(\rightleftharpoons\) 2HI (g)
2
PCl5 (g) \(\rightleftharpoons\) PCl3 (g) + Cl2 (g)
3
N2 (g) + 3H2 (g) \(\rightleftharpoons\) 2NH3 (g)
4
The equilibrium will remain unaffected in all the three cases.