This chemistry website is aimed mainly at senior high school students for NEET , JEE and first year university students. It covers general chemistry topics required in School, Colleges and Universities. However, chemistry topics of general interest are going to be included.
Which of the following statements for order of reaction is not correct? [IIT JEE 2005]
Order can be determined experimentally
Order of a reaction is equal to the sum of the power of concentration terms in differential rate law
It is not affected with the stoichiometric coefficients of the reactants
Order cannot be fractional
The rate of reaction between two reactants A and B decreases by a factor of 4 if the concentration of reactant B is doubled. The order of reaction with respect to reactant B is [CBSE AIPMT 2005]
2
-2
1
-1
A reaction involving two different reactants can never be [AIEEE 2005]
Unimolecular reaction
First order reaction
Second order reaction
Bimolecular reaction
Consider an endothermic reaction, X → Y with activation energies Eb and Ef respectively for the backward and forward reactions, respectively. In general, [AIEEE 2005]
Eb < Ef
Eb > Ef
Eb = Ef
there is no definite relation between Eb and Ef
t1/4 can be taken as the time taken for the concentration of a reactant to drop to 3/4 of its initial value. If rate constant for a first order reaction is k, then t1/4 can be written as [AIEEE 2005]
0.29/k
0.45/k
0.1/k
4.5/k
A follows first order reaction, (A) → product
Concentration of A, changes from 0.1 M to 0.025 M in 40 minutes. Find the rate of reaction of A when concentration of A is 0.01 M. [IIT JEE 2004]
3.47 × 10^–5 M min^–1
3.47 × 10^–4 M min^–1
2.47 × 10^–5 M min^–1
1.47 × 10^–5 M min^–1
The rate of a first order reaction is
1.5 × 10–2 mol L–1 min–1 at 0.5 M concentration of the reactant. The half life of the reaction is [CBSE AIPMT 2004]
3.1 min
38.45 min
2.1 min
23.1 min
In a first order reaction, the concentration of the reactant decreases from 0.8 M to 0.4 M in 15 minutes. The time taken for the concentration to change from 0.1 M to 0.025 M is [AIEEE 2004]
10 min
20 min
30 min
45 min
The rate equation for the reaction:
2A + B → C is found to be: rate = k [A] [B]. The correct statement in relation to this reaction is that the [AIEEE 2004]
units of k must be s–1
value of k is independent of the initial concentration of A and B
t1/2 is constant
rate of formation of C is twice the rate of disappearance of A
The velocity constant of a reaction at 290° K was found to be 3.2 × 10–3 S–1. When the temperature is raised to 310° K, it will be about: [Karnataka CET 2004]
1.28 × 10^(–2)
2.28 × 10^(–2)
3.28 × 10^(–2)
4.28 × 10^(–2)
The reaction: A → B follows first order kinetics. The time taken for 0.8 mol of A to produce 0.6 mol of B is 1 hour. What is the time taken for conversion of 0.9 mol of A to produce 0.675 mol of B? [CBSE AIPMT 2003]
60 min
120 min
180 min
6 min
The rate law for a reaction between the substances A an B is given by Rate = k [A]n [B]m
On doubling the concentration of A and halving the concentration of B, the ratio of the new rate to the earlier rate of reaction will be [AIEEE 2003]
1.8 x 2^(n – m)
2^(n – m)
m-n
m+n
In respect of the equation K = Ae–Ea / RT in chemical kinetics, which one of the following statements is correct? [AIEEE 2003]
k is equilibrium constant
R is Rydberg's constant
Ea is energy of activation
A is adsorption factor
Units of rate constant of first and zero order reactions in terms of molarity M unit are respectively [AIEEE 2002]
sec^–1, M
M, sec^–1
sec^–1, Msec^–1
m.C
When a bio chemical reaction is carried out in laboratory out side the human body in the absence of enzyme, then the rate of reaction obtained is 10–6 times, than activation energy of
reaction in the presence of enzyme is: [AIPMT 2001]
Different from, Ea obtained in laboratory
Can't say any things
P is required
6/RT
Which one of the following is a second order reaction? [Karnataka CET 2007]
H2 + Br2 → 2BHr
NH4NO3 → N2 + 3H2O
H2 + Cl2 (Sun light)------>2HCl
CH3COOCH3 + NaOH → CH3COONa + H2O
Consider a reaction, aG + bH → Products.
When concentration of both the reactants G and H is doubled, the rate increases by eight times. However, when the concentration of G is doubled keeping the concentration of H fixed, the rate is doubled. The overall order of the reaction is: [IIT JEE 2007]
0
1
2
3
If 60% of a first order reaction was completed in 60 minutes, 50% of the same reaction would be completed in approximately [CBSE PMT 2007]
45 minutes
55 minutes
65 minutes
25 minutes
Consider the reaction,
2A + B → Products
When concentration of B alone was doubled, the half-life did not change. When the concentration of A alone was doubled, the rate increased by two times. The unit of rate constant for this reaction is: [AIEEE 2007]
mol L–1 s–1
L mol–1 s–1
s–1
unit less
The energies of activation for forward and reverse reactions for A2 + B2 2AB are 180 kJ mol–1 and 200 kJ mol–1 respectively. The presence of a catalyst lowers the activation energy of both (forward and reverse) reactions by 100 kJ mol–1. The enthalpy change of the reaction (A2 + B2 → 2AB) in the presence of catalyst will be (in kJ mol–1): [AIEEE 2007]
2A + B → Products
When concentration of B alone was doubled, the half-life did not change. When the concentration of A alone was doubled, the rate increased by two times. The unit of rate constant for this reaction is: [AIEEE 2007]
120
20
280
300
For a reaction A + B → C + D if the concentration of A is doubled without altering the concentration of B, the rate gets doubled. If the concentration of B is increased by nine times without altering the concentration of A, the rate gets tripled. The order of the reaction is [Karnataka CET 2006]
2
3/2
1
3
A reaction was found to be second order with respect to concentration of carbon monoxide. If the concentration of carbon monoxide is doubled, with everything else kept the same, the rate of reaction will [AIEEE 2006]
3x
increase by a factor of 4
2x
remain unchanged
Rate of a reaction can be expressed by Arrhenius equation as:
k = Ae–E/RT
In this equation, E represents [AIEEE 2006]
the total energy of the reacting molecules at a temperature, T.
the fraction of molecules with energy greater than the activation energy.
the energy above which all the colliding molecules will react.
the energy below which colliding molecules will not react
For the reaction A + B → C, it is found that doubling the concentration of A increases the rate by 4 times, and doubling the concentration of B doubles the reaction rate. What is the overall order of the reaction? [Karnataka CET 2005]
3
3/2
2
4
Which of these does not influence the rate of reaction? [Karnataka CET 2005]
Molecularity of the reaction
Nature of the reactants
Concentration of the reactants
Temperature of the reaction
The time for half life period of a certain reaction A → Products is 1 h. When the initial concentration of the reactant 'A' is 2.0 mol L–1, how much time does it take for its concentration to come from 0.50 to 0.25 mol L–1, if it is a zero order reaction? [AIEEE 2010]
5 hr
2.87 hr
0.25 hr
5 hr
The time taken for 10% completion of a first order reaction is 20 min. Then, for 19% completion, the reaction will take [WB JEE 2009]
60 min
20 min
30 min
40 min
The rate equation for a reaction: A → B is r = K [A]°. If the initial concentration of the reactant is a mol dm–3, the half life period of the reaction is [Karnataka CET 2009]
a/2k
a/k
k/a
45
For the reaction A + B → products, it is observed that
(i) On doubling the concentration of A only, the rate of reaction is also doubled.
(ii) On doubling the initial concentration of both A and B, there is change by a factor of 8 in the rate of reaction.
The rate of reaction is given by [CBSE AIPMT 2009]
rate = k [A]3 [B]2
rate = k [A] [B]2
rate = k [A]4 [B]2
rate = k [A]2 [B]
Under the same reaction conditions, initial concentration of 1.386 mol dm–3 of a substance becomes half in 40 seconds and 20 seconds through first order and zero order kinetics respectively. Ratio of the rate constants for first order (k1) and zero order (k0) of the reaction is [IIT JEE 2008] ( unit in mol^(–1) dm^3
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