2 moles of N₂ are mixed with 6 moles of H₂ in a closed vessel of one litre capacity. If 50% N₂ is converted into NH₃ at equilibrium, the value of K_c for the reaction,

$N_2\left(g\right)+3H_2\left(g\right)\rightleftharpoons 2N{H}_3\left(g\right)$