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

1/2 t for a zero order reaction is …(I)… proportional to the initial concentration of the reactants and …(II)… proportional to the rate constant. Choose the correct words to fill up the blanks (I) and (II) respectivel…

…A… of the reaction is the time in which the concentration of a reactant is reduced to one half of its initial concentration. Choose the appropriate word to fill ‘A’ from the options given below.

For a given reaction half life period was found to be directly proportional to the initial concentration of the reactant. The order is

What will be the half-life of the first order reaction for which the value of rate constant is 200 s–1?

The half-life period of a first order reaction is

In a first order reaction, reactant concentration ‘C’ varies with time ‘t’ as

In a first order reaction the concentration of reactant decreases from 800 mol/dm3 to 50 mol/dm3 in 2 × 104 sec. The rate constant of reaction in sec–1 is:

For a first order reaction, (A) -> product the concentration of A changes from 0.1 M to 0.025 M in40 min. The rate of reaction when the concentration of A is 0.01 M is

The correct expression for the rate constant for reactions of zero-order is

If ‘a’ is the initial concentration of the reactant, the time taken for completion of the reaction, if it is of zero-order, will be

For a general reaction X -> Y, the plot of conc. of X vs time is given in the figure. What is the order of the reaction and what are the units of rate constant?

The rate constant of a first order reaction is 15 ×10-3 s–1. How long will 5.0 g of this reactant take to reduce to 3.0 g?

1.386 hours are required for the disappearance of 75% of a reactant of first-order reaction. What is the rate constant of the reaction?

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…