A+B⇌C+D . Initially the concentration of A and B are both equal but at equilibrium concentration of D will be twice of that of A then what will be equilibrium constant of reaction

A   +    B    ⇌    C   +   D 1            1             0           0     Initial (1-x)   (1-x)      x           x     AT Equilibrium D=2[A] x=2(1-x) x=2-2x x=23 kC=x2(1-x)2=(x1-x)2 =((23)2(13)2) =22=4