NEET Exam Model Paper 10

For the reaction
2A+B→3C+D
Rate constant of first – order reaction
k=

2.303

t

log10

(A)0

(A)t

or k=

2.303

1

×log10

0.8

0.1

....(i)
(because 0.6 mole of-0.225 B is formed)Suppose t1 hour is required for changing the concentration of A from 0.9 mole to 0.675 mole of B. Remaining mole of A=0.9
−0.675−0.225
∴k=

2.303

t

log10

0.9

0.225

.....(ii)
From Eqs (i) and (ii)
2.303log104=

2.303

t

log104
t1=1hr