Question

Consider the reaction,

A + B $\to$ C + D, if the concentration of A is doubled without altering the concentration of B, the rate gets doubled. If the concentration of B is increased by nine times without altering the concentration of A, the rate gets tripled. The order of the reaction is?

• A. 1.5

Answer 1

The correct option is A 1.5
Rate = $k[A{]}^{\alpha }.[B{]}^{\beta }$ ....... (i)
$2\times Rate=k[2A{]}^{\alpha }.[B{]}^{\beta }$ ....... (ii)
$3\times Rate=k[A{]}^{\alpha }.[9B{]}^{\beta }$ ....... (iii)

From equation (i) and equation (ii), $\alpha =1$
From equation (i) and equation (iii), $\beta =\frac{1}{2}$

Order = $\alpha +\beta =\frac{3}{2}$ =1.5