Question #d3beb

1 Answer
Jul 24, 2016

46) Let initial conc. be #c M#
The change in conc. in first 20s is #0.2cM# So rate of change of conc. in first 2mins is #(0.2c)/20=0.01cM/"min"#

The change in conc. in first 30s is #0.3cM# So rate of change of conc. in first 20min is #(0.3c)/30=0.01cM/"min"#

The rate of change of conc.being independent of time interval i.e.So it is Zero order reaction.

47) We known the velocity constant of first order reaction is
#k=2.303/t*log_10(a/(a-x))#
Where a is the initial conc.of reactant x is the change in conc. after time 't'

#"Here " t =10 min and x=(90a)/100#

#k=2.303/10*log_10(a/(a-(90a)/100))=0.2303min^-1#

48 In this problem the half life or the time for 50% consumption of reactant is 0.231min.
This means when t =0.231min
#x=(50a)/100#

So Velocity constant of the first order reaction

#k=2.303/t*log_10(a/(a-x))#

#k=2.303/ 0.231*log_10(a/(a-(50a)/100))#

#k=2.303/0.231*log_10 2=3.001#