PRACTICE TEST
Single Correct Choice Type
1. Mechanism of the reaction is: (all the reactions are of 1st order)
nk k
A n A A1
2k
3k
A3
d A1
What is the dt for same time.
d A
dt
1
(A) n (B)
n n 1
2 n
(C) (D)
n n 1 n n 1
2. The hydrolysis of an ester was carried out with 0.1 N H2SO4 and 0.1 N HCl separately.
Which of the following expressions between the rate constants is expected?
The rate expression being rate = k’[ester] [H+][H2O]
rate = k[ester]
(where k = k’[H+][H2O])
(A) k HCl k H2SO4 (B) k HCl kH2SO4
(C) k HCl k H2SO4 (D) kH2SO4 2kHCl
3. 2N2O5 g 4NO2 g O2 g
d N2O5 d NO2 d O2
k1 N2O5 , k 2 N2O5 , k 3 N2O5
dt dt dt
What is the relation between k1, k2 & k3?
(A) k1= k2 = k3 (B) 2 k1= k2 = 4 k3
(C) 2 k1= 4 k2 = k3 (D) None of these
4. In a vessel of capacity 1 litres at 27 oC for the first order decomposition of
C2H5Br g C2H4 g HBr g
If inert gas is also present in vessel, the initial pressure of 200 mm of Hg changes to 390 mm
of Hg after infinite time, where all the reactant is consumed, if at 10 min, 0.2 g of NaOH was
required to react completely with reaction mixture, find out the half life of the reaction?
(A) 10 min (B) 20 min
(C) 50 min (D) 100 min
A
k
Product, B
k
5. T
A
T
B
Product
A B
Two reaction with half life periods TA, TB (in mins) and kA(min–1) and kB(in mol–1 lit.min–1). If
half life periods are equal at the start of reaction, the reaction rate ratio at the start of
reaction would be (assume [A]0 = [B]0)
1
(A) (B) 0.693
0.693
(C) log 2 (D) None of these
6. The rate law for the dimerization of NO 2 is:
2NO2 g N2O4 g
d NO2
k NO2
2
dt
Which of the following will change the value of specific reaction rate?
(A) Doubling the total pressure of system
(B) Doubling the volume of the container
(C) Adding more NO2 to the reaction mixture
(D) Running the reaction in CCl4 solution rather than in gas phase
k1
7. For elementary reaction 2 A B , the rate of disappearance of A is equal to
k2
(A) k1[A]2 – k2[B] (B) 2 k1[A]2 – 2 k2[B]
(C) -2 k1[A]2 – 2 k2[B] (D) (2 k1 – k2)[A]
8. In chemical kinetics, only a small fraction of collisions lead to reaction. This is because
(A) The colliding molecules may not be appropriately oriented to one another and the
collisions are not energetic.
(B) The colliding molecules are properly oriented to one another and the collisions are highly
energetic.
(C) The colliding molecules are properly oriented to one another and the collisions are not
highly energetic.
(D) The colliding molecules may not be appropriately oriented to one another and the
collisions are very energetic.
9. The high temperature( 1200 K) decomposition of CH3COOH(g) occurs as follows as per
simultaneous 1st order reactions.
k1
CH3COOH CH4 CO2
k
CH3COOH
2
CH2CO H2O
What would be the % of CH4 by mole in the product mixture(excluding CH3COOH)?
50K1 100K1
(A) (B)
K1 K 2 K1 K 2
200K1
(C) (D) it depends on time
K1 K 2
10. In the reaction, A 2B Product
Rate = k[A]1[B]0
The initial concentration of both A and B are x molar. The graph of concentration of B vs time
is(t1 = t½ for A)
X
X
(A) (B)
[B] [B]
t t1 t t1
X
X
(C) (D)
[B] B
t t1 t t1
11. What is the order with respect to A, B, C respectively
[A] [B] [C] rate(M/sec)
0.2 0.1 0.02 8.08 10–3
0.1 0.2 0.02 2.01 10–3
0.1 1.8 0.18 6.03 10–3
0.2 0.1 0.08 6.464 10–2
(A) -1, 1, 3/2 (B) -1, 1, 1/2
(C) 1, 3/2, -1 (D) 1, -1, 3/2
Multiple Correct Choice Type
12. For a reaction A B, Ea for the forward reaction (Ea)f and backward reaction (Ea)b is
19 kJ/mole and 9 kJ/mole respectively. Potential energy of A is 12 kJ/mole
Find out which of the following options are correct?
(A) Heat of reaction is 10 kJ/mol
(B) It is an exothermic reaction
(C) The threshold energy of reaction is 31 kJ/mol
(D) The potential energy of product is 22 kJ/mol
13. Which of the following statements are correct?
(A) Order of reaction is an experimental determined quantity
(B) Order may change with change in experimental conditions
(C) Molecularity concerns with mechanism while order concerns with kinetics
(D) A reaction taking place by bimolecular collision must always be of second order
14. Identify the true statement(s)
(A) A catalyst is chemically unchanged at the end of a reaction
(B) A catalyst may appear in the kinetic rate equation of the reaction
(C) A catalyst will not affect the composition of an equilibrium mixture
(D) A catalyst cannot cause a non-spontaneous(G > 0) reaction to proceed
15. Which of the following statement(s) is/are correct?
(A) Zero order reactions are complex reactions
(B) A reaction having first order may be either elementary or complex reaction
(C) A reaction having second order reaction must have molecularity = 2
(D) A reaction with molecularity = 2 must be a second order reaction
16. For the consecutive reaction. A
k1 time1
B
k 2 time1
C following curves were obtained
depending upon the relative values of k 1 and k2.
C A
Conc Conc
X
B
A
B
X
Time X Time
Figure – 1 Figure – 2
Now, which of the following is correct match?
(A) Figure 1 – (k1 < k2) (B) Figure 2 – (k1 < k2)
(C) Figure 2 – (k1 >> k2) (D) Figure 1 – (k1 >> k2)
17. Which is correct graph?
Second. order First order
(A) t0.75
(B) dc
n
dt
a (Initial concentration)
time
At given conc.
and order
t0.75
(C) dc (D) First order
n t0.5
dt
1/temp a (Initial concentration)
18. Consider the following case of competing 1st order reactions.
k1 C
A
k2 D
After the start of the reaction at t = 0 with only A, the [C] is equal to the [D] at all times. The
time in which all three concentration will be equal is given by;
1 1
(A) t n3 (B) t n3
2k1 2k 2
1 1
(C) t n2 (D) t n2
3k1 3k 2
19. Rate of a chemical reaction 2 A g B g is defined as:
1 dnB
'rB '
V dt
Where nB = number of moles of B formed and CB = concentration of B then which of the
following relation is correct.
dCB CB dV
(A) rB If volume V isnot const an t
dt V dt
dCB
(B) rB If volume V const an t
dt
dCB CB dV
(C) rB If volume V isnot const an t
dt V dt
dC C dV
(D) rB B B If volume V isnot const an t
dt V dt
Matrix – Match Type
20. Match the following:
Column – I Column – II
2N2O5 g 4NO2 g O2 g
(A) st
1 order (P) All the gaseous products are
paramagnetic in nature
(B) (Q) Hybridisation of reactant
2H2O2 aq 2H2O aq O2 g
st
1 order
involves only s & p orbitals
(C) 2NH3 g
Zero order
N2 g 3H2 g (R) As the reaction proceeds half life
of reactant changes with time
(D) 2Cl2O7 g
Zero order
4ClO2 g 3O2 g (S) rate of production of gases
decreases with increase in
concentration of products
(T) rate of consumption of reactants
does not change with time
Numerical Type
21. For a second order reaction
T75% = Xt50%
Find the value of X
22. For the reaction A Products, the following data is given for a particular reaction.
time(min) 0 5 15 35
1
A
M1
1 2 4 8
Determine the order of reaction.
ANSWERS
1. C 2. A 3. B 4. A
5. B 6. D 7. B 8. A
9. A 10. B 11. D 12. ACD
13. ABC 14. ABCD 15. AB 16. BD
17. ABC 18. AB 19. AB
20. A PQS B PQS C QRT D PQRT
21. 3 22. 2
