For the reaction

CHEMISTRY · Single correct · A Level · Chemistry · Chemical equilibria (Le Chatelier’s principle and Kc) · Chemical equilibria (Le Chatelier’s principle and Kc)

Problem

For the reaction PCl5(g)⇌PCl3(g)+Cl2(g)\mathrm{PCl_5(g) \rightleftharpoons PCl_3(g)+Cl_2(g)}, the equilibrium constant at 400\,K is Kc=0.042K_c=0.042. Three sealed flasks (I–III) each contain the gases at 400\,K in the following molar concentrations (in mol L−1\text{mol\,L}^{-1}). • Flask I: [PCl5_5] = 0.20, [PCl3_3] = 0.10, [Cl2_2] = 0.10 • Flask II: [PCl5_5] = 0.30, [PCl3_3] = 0.050, [Cl2_2] = 0.050 • Flask III: [PCl5_5] = 0.25, [PCl3_3] = 0.12, [Cl2_2] = 0.080 Which ranking correctly orders the flasks from the greatest tendency to shift toward products to the greatest tendency to shift toward reactants? (a) II > I > III (b) II > III > I (c) I > III > II (d) III > II > I

Related theory

Browse the problem library