Law of mass action definition and derivation

➤  Law of Mass Action  💕

It states that “the rate at which a substance reactis proportionalto its active mass and the rate of chemical reaction is proportional to the product of the active masses of the reacting substances.”
Law of Mass Action is applicable to Reversible Reaction in Equilibrium:

Consider a general reaction

Reactants are converted into product and the products are
 reconverted into reactants under same conditions until it
  reached to equilibrium.
        A   +   B     ⇌  C    +  D
Rate of Forward Reaction 𝛂 [A][B]

Rf = Kf [A][B]

Rate of Reverse Reaction 𝛂 [C][D]

Rr = Kr [A][B]


At Equilibrium:

Rate of Forward Reaction ( Rf )= Rate of Reverse reaction(Rr)

                                [C] [D]/ [A] [B]  = Kf/Kr  = Kc

Kc is known as the equilibrium constant.


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