For the cyclic teimerisation of acetylene to give one mole of benzene `K_c=4L^2 mol^-2` IF the equilibrium concentration of benzene is `0.5 mol L^-1` calculate the equilibrium concentration of acetylene.

Explanation

The chemical equilibrium is `3C_2H(g) leftrightarrow C_6H_6 (g)`
`K_c=([C_6H_6])/[C_2H_2]^2=4L^2 mol^-2 [C_2H_2]^3=([C_6H_6])/K_c=1/(2 times 4)=1/(8L mol^-3)`
Equilibrium concentration of acetylene, `[C_2H_2]=0.5 mol L^-1`