In the reaction A  +  2B  $\rightleftharpoons$ 2C, if 2 moles of A, 3.0 moles of B and 2.0 moles of C are placed in a 2.0 L flask and the equilibrium concentration of C is 0.5 mole/L. The equilibrium constant $\left({\mathrm{K}}_{\mathrm{C}}\right)$ for the reaction is

                         A    +    2B   $\rightleftharpoons$   2C  here equilibrium shifted to back

Initial conc.       2            3           2

at eqm.             2.5         4            1

Molar     $\frac{2.5}{2}=1.25$    $\frac{4}{2}=2$    $\frac{1}{2}=0.5$

$K=\frac{{\left[0.5\right]}^2}{\left[1.25\right] \times {\left[2\right]}^2}= 0.05$