Chemical Kinetics · Question 44

The half-life of a substance in a certain enzyme-catalysed reaction is 138 s. The time required for the concentration of the substance to fall from 1.28 mg L-1 to 0.04 mg L-1 is

1. 414 s
2. 552 s
3. 690 s
4. 276 s

Which one of the following statements for the order of a reaction is incorrect?

1. Order can be determined only experimentally.
2. Order is not influenced by stoichiometric coefficient of the reactants.
3. Order of a reaction is sum of power to the concentration terms of reactants to express the rate of reaction.
4. Order of reaction is always whole number.

The rate of the reaction, 2NO + Cl2 2NOCl is given by the rate equation rate = k[NO]2[Cl2]. The value of the rate constant can be increased by

1. increasing the temperature
2. increasing the concentration of NO
3. increasing the concentration of the Cl2
4. doing all of these.

For an endothermic reaction, energy of activation is Ea and enthalpy of reaction is H (both of these in kJ/mol). Minimum value of Ea will be

1. less than H
2. equal to H
3. more than H
4. equal to zero

For the reaction N2O5(g) 2NO2(g) + 12O2(g) the value of rate of disappearance of N2O5 is given as 6.25 10-3 mol L-1 s-1. The rate of formation of NO2 and O2 is given respectively as

1. 6.25 10-3 mol L-1 s-1 and 6.25 10-3 mol L-1 s-1
2. 1.25 10-2 mol L-1 s-1 and 3.125 10-3 mol L-1 s-1
3. 6.25 10-3 mol L-1 s-1 and 3.125 10-3 mol L-1 s-1
4. 1.25 10-2 mol L-1 s-1 and 6.25 10-3 mol L-1 s-1

During the kinetic study of the reaction, 2A + B C + D, following results were obtained array|l|l|l|l| Run & [A]/ mol L-1 & [B]/ mol L-1 & Initial rate of formation \ & & & of D/ mol L-1 min-1 \ I. & 0.1 & 0.1 & 6.0 10-3 \ II. & 0.3 & 0.2 & 7.2 10-2 \ III. & 0.3 & 0.4 & 2.88 10-1 \ IV. & 0.4 & 0.1 & 2.40 10-2 \ array Based on the above data which one of the following is correct?

1. Rate = k[A]2[B]
2. Rate = k[A][B]
3. Rate = k[A]2[B]2
4. Rate = k[A][B]2

For the reaction, N2 + 3H2 2NH3, if d[NH3]dt = 2 10-4 mol L-1 s-1, the value of -d[H2]dt would be

1. 4 10-4 mol L-1 s-1
2. 6 10-4 mol L-1 s-1
3. 1 10-4 mol L-1 s-1
4. 3 10-4 mol L-1 s-1

In the reaction, BrO-3(aq) + 5Br-(aq) + 6H+ 3Br2(l) + 3H2O(l). The rate of appearance of bromine (Br2) is related to rate of disappearance of bromide ions as

1. d[Br2]dt = - 53 d[Br-]dt
2. d[Br2]dt = 53 d[Br-]dt
3. d[Br2]dt = 35 d[Br-]dt
4. d[Br2]dt = - 35 d[Br-]dt

Half-life period of a first order reaction is 1386 s. The specific rate constant of the reaction is

1. 0.5 10-2 s-1
2. 0.5 10-3 s-1
3. 5.0 10-2 s-1
4. 5.0 10-3 s-1

For the reaction A + B products, it is observed that (i) on doubling the initial concentration of A only, the rate of reaction is also doubled and (ii) on doubling the initial concentration of both A and B, there is a change by a factor of 8 in the rate of the reaction. The rate of this reaction is given by

1. rate = k[A]2[B]2
2. rate = k[A][B]2
3. rate = k[A][B]
4. rate = k[A]2[B]