The equilibrium constants for the stepwise formation of MCl, MCl₂ and MCl3 are a, b and c respectively. If the equilibrium constant of formation of MCl₃ is K, which of the following is correct?

: we have, (1) M+½ Cl₂→MCl , K₁=a

(2)MCl+1/2 Cl₂→MCl₂, K₂=b

(3) MCl₂+1/2 Cl₂→MCl₃, K₃= c

(4) M+3/2Cl₂→MCl₃, K=not

So, K₄= K₁×K₂×K₃

Hence, logK= loga+logb+logc

Therefore, the correct answer is option (C) logK = loga+logb+logc.