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______.

Given,

Rate_O = k[A][B], the rate is directly proportional to the unit power of the concentration of element B. So, if its concentration is doubled the rate of reaction is also doubled.

Rate=k[A][2B] 2K[A][B] 2Rate₀

Thus Option (ii) is correct.