Rate law for the reaction \(A+2 B \rightarrow C\) is found to be
Rate = k[A][B]
If the concentration of reactant 'B' is doubled, keeping the concentration of A constant, then the value of the rate of the reaction will  be:

1. The same. 2. Doubled.
3. Quadrupled. 4. Halved.
HINT: Rate of reaction depends on the concentration of reactant.
Explanation:
Rate law can be written as

                         Rate = k[A][B]

The rate of reaction w.r.t B is of the first order.

R1= k[A][B]

When the concentration of reactant B' is doubled then calculate R2 as follows:

R1=k[A][B]R2=k[A][2B]R1R2=12R2=2R1

Therefore, as the concentration of B is doubled keeping the concentration of A constant rate of reaction became doubled.