Question

36. Rate law for the reaction A + 2B - C is found to be
Rate = k [A][B]
Concentration of reactant 'B' is doubled. Keeping the
concentration of 'A' constant, the value of rate constant
will be:
(a) the same
(b) doubled
(c) quadrupled
(d) halved​

Answer 1

QUESTION :

• Rate law for the reaction A + 2B - C is found to beRate = k [A][B] Concentration of reactant 'B' is doubled. Keeping the

concentration of 'A' constant, the value of rate constant will be

SOLUTION :

Initially the rate of the reaction is

R = k [ A ] [ B ]

here ,

• R = rate of the reaction
• k = rate constant
• [ A ] and [ B ] = concentration of reactant

Now keeping the concentration of A constant Concentration of B is doubled

R ' = k [ A ] [ 2 B ]

R ' = 2 k [ A ] [ B ]

R ' = 2 R

Here rate of the reaction doubles but the rate constant remains the same

Rate constant depends only upon temperature ,it doesn't depend upon the concentration of the reactant

ANSWER :

• a ) remains the same

Answer 2

The specific rate constant (k) is the proportionality constant relating the rate of the reaction to the concentrations of reactants. The rate law and the specific rate constant for any chemical reaction must be determined experimentally. The value of the rate constant is temperature dependent.