At equilibrium, \(1\) mole of \(CO\) is present
Hence, \(2-1=1\) moles of \(CO\) has reacted.
\(1\) mole of \(CO\) will react with \(1\) mole of \(Cl_2\) to from \(1\) mole of \(COCl_2\).
\(3-1=2\) moles of \(Cl_2\) remains at equilibrium
The equlibrium constant
\({K_c} = \frac{{[COC{l_2}]}}{{[CO][C{l_2}]}} = \frac{{\frac{{1\,mol}}{{5\,L}}}}{{\frac{{1\,mol}}{{5\,L}} \times \frac{{2\,mol}}{{5\,L}}}} = 2.5\)
[આપેલ : $R=0.082 \,L \,atm\, K ^{-1}\, mol ^{-1}$ ]