PYQSide ExamsMy practice

Chemical Kinetics · Question 26

NEET 2018MCQEasy📈 Topic in 38% papers+4−1
1

The correct difference between first and second order reactions is that

  1. the rate of a first-order reaction does not depend on reactant concentrations; the rate of a second-order reaction does depend on reactant concentrations
  2. the half-life of a first-order reaction does not depend on [A]0; the half-life of a second order reaction does depend on [A]0
  3. a first-order reaction can be catalysed; a second-order reaction cannot be catalysed
  4. the rate of a first-order reaction does depend on reactant concentrations; the rate of a second-order reaction does not depend on reactant concentrations

Answer

(2) the half-life of a first-order reaction does not depend on [A]0; the half-life of a second order reaction does depend on [A]0

Solution

Rate of a first-order reaction = k[A] and of a second-order reaction = k[A]2 ⇒ both depend on concentration ⇒ (1) and (4) are wrong.

Any reaction, whatever its order, can be catalysed ⇒ (3) is wrong.

First order: t1/2 = 0.693k ⇒ independent of [A]0

Second order: t1/2 = 1k[A]0 ⇒ depends on [A]0

Answer: (2)

NEET 2018

Keep practising — Chemical Kinetics

2

When initial concentration of the reactant is doubled, the half-life period of a zero order reaction

  1. is halved
  2. is doubled
  3. is tripled
  4. remains unchanged.
NEET 2018
3

Mechanism of a hypothetical reaction X2 + Y2 2XY, is given below : (i) X2 X + X (fast) (ii) X + Y2 XY + Y (slow) (iii) X + Y XY (fast) The overall order of the reaction will be

  1. 2
  2. 0
  3. 1.5
  4. 1
NEET 2017
4

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

  1. 138.6 sec
  2. 346.5 sec
  3. 693.0 sec
  4. 238.6 sec
NEET 2017
5

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

  1. 44.1 s
  2. 54.1 s
  3. 24.1 s
  4. 34.1 s
NEET 2016 (Phase 1)
6

The addition of a catalyst during a chemical reaction alters which of the following quantities?

  1. Enthalpy
  2. Activation energy
  3. Entropy
  4. Internal energy
NEET 2016 (Phase 1)
7

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

  1. rate is proportional to the surface coverage
  2. rate is inversely proportional to the surface coverage
  3. rate is independent of the surface coverage
  4. rate of decomposition is very slow.
NEET 2016 (Phase 2)
8

The rate constant of the reaction A B is 0.6 10-3 mol L-1 s-1. If the concentration of A is 5 M, then concentration of B after 20 minutes is

  1. 3.60 M
  2. 0.36 M
  3. 0.72 M
  4. 1.08 M
AIPMT 2015
9

The activation energy of a reaction can be determined from the slope of which of the following graphs?

  1. k vs. 1T
  2. T k vs. 1T
  3. k vs. T
  4. kT vs. T
AIPMT 2015 (Cancelled)
10

When initial concentration of a reactant is doubled in a reaction, its half-life period is not affected. The order of the reaction is

  1. second
  2. more than zero but less than first
  3. zero
  4. first.
AIPMT 2015 (Cancelled)
11

A reaction having equal energies of activation for forward and reverse reactions has

  1. H = 0
  2. H = G = S = 0
  3. S = 0
  4. G = 0
NEET 2013

All Chemical Kinetics PYQs →

PDFDownload Chemical Kinetics PYQs as PDF Free, with answer key and a QR code to every solution — print it or study offline⬇
All NEET Chemistry chapters
Physical ChemistrySome Basic Concepts of ChemistryStructure of AtomStates of MatterThermodynamicsEquilibriumRedox ReactionsSolid StateSolutionsElectrochemistryChemical KineticsSurface Chemistry
Inorganic ChemistryClassification of Elements and Periodicity in PropertiesChemical Bonding and Molecular StructureHydrogens-Block Elementsp-Block Elements (Group 13 & 14)Environmental ChemistryGeneral Principles of Isolation of Elementsp-Block Elements (Group 15–18)d- and f-Block ElementsCoordination Compounds
Organic ChemistryOrganic Chemistry – Some Basic Principles and TechniquesIsomerismHydrocarbonsHaloalkanes and HaloarenesAlcohols, Phenols and EthersAldehydes, Ketones and Carboxylic AcidsAminesBiomoleculesPolymersChemistry in Everyday LifePrinciples Related to Practical Chemistry