1.
PCl5PCl3+Cl2\mathrm{PCl_5 \rightleftharpoons PCl_3 + Cl_2}

If the equilibrium constant (Kc_c) for the above reaction at 500 K is 1.79 and the equilibrium concentration of PCl5_5 and PCl3_3 are 1.41 M and 1.59 M, respectively, then the concentration of Cl2_2 is approximately: