# NEET Questions Solved

The plot of log k vs 1/T helps to calculate

1. Energy of activation

2. Rate constant of reaction

3. Order of reaction

4. Energy of activation as well as the frequency factor

Concept Videos :-

#8 | Problems on 1st Order Reaction (Type 1)
#9 | Problems on 1st Order Reaction (Type 2)
#10 | Problems on 1st Order Reaction (Type 3)
#12 | Problems on 1st Order Reaction (Type 5)

Concept Questions :-

First Order Reaction Kinetics
Complete Question Bank + Test Series
Complete Question Bank

Difficulty Level:

Two reactions of the same order have equal Pre-exponential factors but their activation energies differ by 24.9 kJ/mol. Calculate the ratio between the rate constants (K2/K1) these reactions at 27°C :

(1) 3 x 104

(2) 1/3 x 10-4

(3) 1/3 x 104

(4) 3 x 10-4

Concept Videos :-

#8 | Problems on 1st Order Reaction (Type 1)
#9 | Problems on 1st Order Reaction (Type 2)
#10 | Problems on 1st Order Reaction (Type 3)
#12 | Problems on 1st Order Reaction (Type 5)

Concept Questions :-

First Order Reaction Kinetics
Complete Question Bank + Test Series
Complete Question Bank

Difficulty Level:

A first order reaction has a specific reaction rate of 10-2s-1. How much time will it take for 20 g of the reactant to reduce to 5 g?

(a) 238.6 s      (b) 138.6 s        (c) 346.5  s        (d) 693.0 s

Concept Videos :-

#8 | Problems on 1st Order Reaction (Type 1)
#9 | Problems on 1st Order Reaction (Type 2)
#10 | Problems on 1st Order Reaction (Type 3)
#12 | Problems on 1st Order Reaction (Type 5)

Concept Questions :-

First Order Reaction Kinetics
Complete Question Bank + Test Series
Complete Question Bank

Difficulty Level:

The decomposition of phosphine (PH3) on tungsten at low pressure is a first-order reaction. It is because the

(a) rate is proportional to the surface coverage

(b) rate is inversely proportional to the surface coverage

(c) rate is independent of the surface coverage

(d) rate of decomposition is very slow

Concept Videos :-

#8 | Problems on 1st Order Reaction (Type 1)
#9 | Problems on 1st Order Reaction (Type 2)
#10 | Problems on 1st Order Reaction (Type 3)
#12 | Problems on 1st Order Reaction (Type 5)

Concept Questions :-

First Order Reaction Kinetics
Complete Question Bank + Test Series
Complete Question Bank

Difficulty Level:

The rate of a first-order reaction is 0.04 mol L-1 s-1 at 10 sec and 0.03 mol L-1 s-1 at 20 sec after initiation of the reaction. The half-life period of the reaction is

(a) 34.1 s (b) 44.1 s (c) 54.1 s (d) 24.7 s

Concept Videos :-

#8 | Problems on 1st Order Reaction (Type 1)
#9 | Problems on 1st Order Reaction (Type 2)
#10 | Problems on 1st Order Reaction (Type 3)
#12 | Problems on 1st Order Reaction (Type 5)

Concept Questions :-

First Order Reaction Kinetics
Complete Question Bank + Test Series
Complete Question Bank

Difficulty Level:

What is the activation energy for a reaction if its rate doubles when the temperature is raised from 20°C to 35°C?  (R=8.314 J mol-1 K-1)

(a) 342 kJ mol-1

(b) 269 kJ mol-1

(c) 34.7 kJ mol-1

(d) 15.1 kJ mol-1

Concept Videos :-

#8 | Problems on 1st Order Reaction (Type 1)
#9 | Problems on 1st Order Reaction (Type 2)
#10 | Problems on 1st Order Reaction (Type 3)
#12 | Problems on 1st Order Reaction (Type 5)

Concept Questions :-

First Order Reaction Kinetics
Complete Question Bank + Test Series
Complete Question Bank

Difficulty Level:

If 60% of a first order reaction was completed in 60 min, 50% of the same reaction would be completed in approximately.

(a) 50 min
(b) 45 min
(c) 60 min
(d) 40 min

(log 4=0.60, log 5=0.69)

Concept Videos :-

#8 | Problems on 1st Order Reaction (Type 1)
#9 | Problems on 1st Order Reaction (Type 2)
#10 | Problems on 1st Order Reaction (Type 3)
#12 | Problems on 1st Order Reaction (Type 5)

Concept Questions :-

First Order Reaction Kinetics
Complete Question Bank + Test Series
Complete Question Bank

Difficulty Level:

The rate of  a reaction becomes four times when the temperature changes from 293 K to 313 K. Calculate the energy of activation (Ea) of the reaction assuming that it does not change with temperature. [R=8.314 J K-1 mol -1, log =0.6021]

Concept Videos :-

#8 | Problems on 1st Order Reaction (Type 1)
#9 | Problems on 1st Order Reaction (Type 2)
#10 | Problems on 1st Order Reaction (Type 3)
#12 | Problems on 1st Order Reaction (Type 5)

Concept Questions :-

First Order Reaction Kinetics
Complete Question Bank + Test Series
Complete Question Bank

Difficulty Level:

The following data were obtained during the first order thermal decomposition of SO2Cl2 at a constant volume :

SO2Cl2(g) $\to$SO2 (g) + Cl2(g)

Experiment           time/s-1              Total pressure/atm

1                        0                          0.4

2                     100                          0.7

Calculate the rate constant.

(Given :log 4 = 0.6021, log 2 = 0.3010)

a) 3.386

b) 2.386

c) 1.986

d)1.386

Concept Videos :-

#8 | Problems on 1st Order Reaction (Type 1)
#9 | Problems on 1st Order Reaction (Type 2)
#10 | Problems on 1st Order Reaction (Type 3)
#12 | Problems on 1st Order Reaction (Type 5)

Concept Questions :-

First Order Reaction Kinetics
Complete Question Bank + Test Series
Complete Question Bank

Difficulty Level:

Hydrogen peroxide, H2O2 (aq) decomposes to H2O(l) and O2(g) in a reaction that is first order in H2O2 and has a rate constant k = 1.06$×$10-3 min-1.

(i) How long will it take for 15% of a sample of H2O2  to decompose?

(ii) How long will it take for 85% of a sample  to decompose?

Concept Videos :-

#8 | Problems on 1st Order Reaction (Type 1)
#9 | Problems on 1st Order Reaction (Type 2)
#10 | Problems on 1st Order Reaction (Type 3)
#12 | Problems on 1st Order Reaction (Type 5)

Concept Questions :-

First Order Reaction Kinetics