In the presence of acid, the initial concentration of cane sugar was reduced from 0.2 M to 0.1 M in 5 h and to 0.05 M in 10 h. The reaction must be of

Options

A. zero order
B. first order
C. second order
D. fractional order

Answer

B

Explanation

For the first order reaction
Rate `prop[A] implies ([A])/("Rate")="Constant"(k)`
(i) When `Deltax=0.2-0.1=0.1, Deltat=5h,[A]=0.2`
Hence, `(0.2)/(0.1//5)=10=k`
(ii) When `Deltax=0.1-0.05=0.05,Deltat=5h,[A]=0.1`
Hence, `(0.1)/(0.05//5)=10=k`
Hence, reaction follows first order rate law.