Question

A reaction is first order with respect to the reactant A and second order with respect to the reactant B in a reaction $A+B\to$product.
i) Write the differential rate equation.
ii) How is the rate of the reaction affected on increasing the concentration of B by two times?

Answer 1

i) The differential rate equation.
rate $=-\frac{d\left[A\right]}{dt}=-\frac{d\left[B\right]}{dt}=k\left[A\right][B{]}^2$
ii) The rate of the reaction is quadrapued on increasing the concentration of B by two times.
$r=k\left[A\right][B{]}^2$.....(1)
$r^{\prime }=k\left[A\right][2B{]}^2$
$r^{\prime }=k\left[A\right]\times 4[B{]}^2$
$r^{\prime }=4\times k\left[A\right][B{]}^2$......(2)
Substitute equation (1) in equation (2)
$r^{\prime }=4\times r$