Question

The initial concentration of cane sugar is presence of an acid was reduced from 0.20 to 0.1M in 5hours and to 0.05M in 10hours value of K ?

Ans .0.1368/hour pls put it on paper

Answer 1

From unit of k in the option ,you can determine the order of reaction.Here hour^-1 >1st order reaction.
Or else
Assume reaction is 1st order reaction

case 1
At=Concentraion at time t
A0=intial concentration
t-time
case 1:
t1=5
At1=0.1
log[At1/A0] = -kt1
ln[A0/At1] = kt
=>k=ln[0.2/0.1]/5
=0.1386/hour
case 2
At2=0.05:
t2=10
log[At2/A0] = -kt2
ln[A0/At2] = kt
=>k=ln[0.2/0.05]/10
=0.1386/hour
There ofr evalue of k is same for both reactions
So the reaction is first order and value of k=0.1386/hour =>Our assumption was correct.
If we assume reaction is any other order(0,2,..etc),value of k will be different for both cases.