if intial conc. of [A]& [oh-] are 0.002m & 0.3m respectively & if it takes for 1y. A to react at 25c, calculate rate constant for rxn.
Ans:- A + On-  Products
Question - 1. A requires activates energy of 20 . When a 20% sol. of A mas kept at 250C for 20 min, 25% decomposition took place. What will be % decomposition in same time in a 30% sol. maintained at 400C. Assume Eq remains constant ?
Ans:_ Given A B
& 20% sol. of A decomposes 25% in 20 min. at 250C
Let Initial amount, a = 20
 amount left (a - x) = 20 X  = 15
 t = 20)
= 0.0144 min-1
 t = 20)
Now, Suppose amount m is left in 30% sol. in 20 min. at 400C.
% discount = 
= 67.21 %
If initial conc. of A is A0, Calculate.
(a) integrated form of rate expresion.
(b) half life period.
Ans:- (a)
at t=0, A=A0
 
By eqn(1) and (ii)
if t=t1/2, A=
Q3: for homogeneous gaseous phase rXb.
2A-> 3b+c , intial pressure of reactant was p while pressure at time t was p. find pressure after time 2t. rXn is ist order
Ans: 2a(9)->3B+c(9)
let total pressure at t=2t be b, then p0-2x+3x+x=B 0+2x=B
by eq (ii) and (iv)
Q4: if rxn Aproducts, concentration
of reactant
A are coaco,a2co,
a3co.... after time interval 0, t, 2t, 3t... where a is constant
. show that rxn is (1) order . also calculate relation in k, a& t.
Ans:- for i order rxn k=
k comes out constant so, rxn is ist order also,
rate constant of decomposition is 4.70x10-3min-1
calculate rate of intial rate of diffusion to rate of diffusion after 45 hr.
of intial of decomposition
assume composition of gas pressent & gas deffusion remains same.
Ans:- CH3oCH9CH4(9)+H9(9)
pressure at t = 0 0 0 0
at t= 4.5 hr 0.4-a=A a a a
A=0.11 0.4-a=0.11a=0.29 now mol wt of mix
=18.78
Hard type Q1: show that time t1/2/ts/4 for nth order rxn is function of n alow. tz/a is time required for conc. to become 1/4th of original conc.
ans: Aproduct
at t=0, c=co
by eq.(1) and(2)
from eq (3) if t= t1/2, c= c0/2
kt3/4,c=c0/4
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