Chemistry Question Bank

A first order reaction is found to have a rate constant, k = 4.2 × 10-12 s-1. Find the half-life of the reaction

Which of the following statement(s) is/are true?

Expression for the half-life of zero order reaction is given as (a) 1/2 R t 2k (b) 0 1/2 R t 2k (c) 1/2 0.693 t k (d) 1/2 0.301 t k Ans. (b) Sol. 0 1/2 R t 2k For a zero order reaction.

Value of 1/2 t for first order reaction is (a) (b) (c) (d) Ans. (a) Sol. Value of t1/2 for first order reaction is 0.693 k

For the first order reaction A ⟶ Products, which one of the following is the correct plot of log [A] versus time? (a) (b) (c) (d)

The rate constant for a zero order reaction is 2 × 10–2 mol L–1 sec–1. If the concentration of the reactant after 25 sec is 0.5 M, the initial concentration must have been

…A… dependence of rate is called differential rate equation. Choose the suitable word to replace A.

Assertion (A) Molecularity of a reaction can have a fractional value. Reason (R) Order of a reaction can have a fractional value.

Assertion (A) The reaction, H Br 2HBr -> has a molecularity of two. Reason (R) Order of reaction is 3/2.

The reaction, 2N O 4NO O is

Four reactions are given below. Which one of them is of zero order? (a) PCl PCl Cl -> (b) 2FeCl SnCl 2FeCl SnCl -> (c) H Cl 2HCl -> (d) N O 2NO O -> Ans. (c) Sol. The order of all photochemical reactions is zero …

Choose the correct answer out of the following choices. Assertion (A) Order and molecularity are different. Reason (R) Order can be determined experimentally and molecularity is the sum of the stoichiometric coefficie…

Choose the correct answer out of the following choices. Assertion (A) Some zero order reactions may have order in fractions. Reason (R) Order cannot be determined from balanced chemical equation.

Which of the following statement(s) is/are correct about order of a reaction? I.The order of a reaction can be a fractional number. II.Order of a reaction is experimentally determined quantity. III.The order of a reac…

Consider the data given below for a hypothetical reactions M N -> Times(s) Rate of reaction (mol L-1 s-1) 4.20 × 10-4 4.20 × 10-4 4.20 × 10-4 4.20 × 10-4 4.18 × 10-4 For the above data, the order of reaction is

Statement I For a complex reaction, order is given by the slowest step of the reaction. Statement II Molecularity of the slowest step is same as the order of the overall reaction. Which of these statement(s) is/are tr…

2NO O 2NO ->

2HI H I -> C. Trimolecula r

NH NO N 2H O -> B. Bimolecular

The following mechanism has been proposed for a reaction. 2P Q R S P Q T R Slow P T R fast -> -> -> The rate law expression for the reaction is (a) r k P Q (b) r k P (c) r k P T (d) r k P Q

For a reaction, 2NO 2H N 2H O, -> the possible mechanism is 2NO N O slow N O H N O H O -> fast N O H N H O -> What is the rate law and order of the reaction? (a) Rate = [N2O2], order =

The chemical reaction, proceeds as O O [O] (fast) [O] O 2O -> (slow) The rate law expression will be

In the sequence of reaction k k k A B C D -> -> -> k3 > k2 > k1, then the rate determining step of the reaction is :

The overall rate of the reaction is controlled by the ______ step in a reaction. Choose the suitable word to fill the blank.

For the reaction 2A + B ⟶ D + E the following mechanism has been proposed : A + B ⟶ C + D (slow) A + C ⟶ E (fast) The rate law expression for the reaction is