The rates of a certain reaction (dc/dt) at different times are as follows 

Time	Rate $\left({\text{mole litre}}^{-1}{\sec }^{-1}\right)$
0	$2.8\times {10}^{-2}$
10	$2.78\times {10}^{-2}$
20	$2.81\times {10}^{-2}$
30	$2.79\times {10}^{-2}$

The reaction is