Question

The initial concentration of sugar solution is $0.12M$. On doing fermentation the concentration of sugar decreases to $0.06M$ in $10h$and to $0.045M$ in $15h$. The order of the reaction is

• A. 0.5
• B. 1.0
• C. 1.5
• D. 2.0

Answer 1

Answer: (B)

$0.12M\stackrel{10h}{\to }0.06M;t_{50}\%=10h$
$0.12M\stackrel{15h}{\to }0.045M;t_{62.5\%}=15h$
$0.12M\stackrel{20h}{\to }0.03M;t_{75\%}=20h$
For first order reaction,
$t_{75\%}=t_{50\%}\times 2$
Hence, this is a first order reaction. Further on putting the values in first order reaction, the value of $k$ remains constant, hence it is a first order reaction.