The given process is reverse of the common Haber's process , which is synthesis of ammonia from nitrogen and hydrogen and that is an exothermic reaction
In the given reaction the the enthalpy change is positive hence it is endothermic reaction
2NH3 (g) ↔ N2 (g) + 3H2 (g) ΔH° =46.1 kJ
i) for endothermic reaction if we increase the temperature the forward reaction goes faster hence first option is incorrect
ii) if we decrease the concentration of either product the reaction will again go in forward direction , so the option decreasing concentration of N2 is also wrong
iii) if we reduce the volume of container it means we are increasing the moles / volume, hence reaction will go in the direction where the number of moles of gaseous molecules is less so reaction will go in backward direction
