Chemical Kinetics · Question 55

The bromination of acetone that occurs in acid solution is represented by this equation. CH3COCH3(aq) + Br2(aq) CH3COCH2Br(aq) + H+(aq) + Br-(aq) These kinetic data were obtained for given reaction concentrations. array|c|c|c|c| [CH3COCH3], M & [Br2], M & [H+], M & Initial rate, disappearance of Br2, M s-1 \ 0.30 & 0.05 & 0.05 & 5.7 10-5 \ 0.30 & 0.10 & 0.05 & 5.7 10-5 \ 0.30 & 0.10 & 0.10 & 1.2 10-4 \ 0.40 & 0.05 & 0.20 & 3.1 10-4 \ array Based on these data, the rate equation is

1. Rate = k[CH3COCH3][Br2][H+]2
2. Rate = k[CH3COCH3][Br2][H+]
3. Rate = k[CH3COCH3][H+]
4. Rate = k[CH3COCH3][Br2]

If 60% of a first order reaction was completed in 60 minutes, 50% of the same reaction would be completed in approximately (log 4 = 0.60, log 5 = 0.70)

1. 45 minutes
2. 60 minutes
3. 40 minutes
4. 50 minutes

In a first-order reaction A B, if k is rate constant and initial concentration of the reactant A is 0.5 M, then the half-life is

1. 2k
2. 2k 0.5
3. 2k
4. 0.6930.5k

The reaction of hydrogen and iodine monochloride is given as: H2(g) + 2ICl(g) 2HCl(g) + I2(g) This reaction is of first order with respect to H2(g) and ICl(g). The following mechanisms were proposed. Mechanism A: H2(g) + 2ICl(g) 2HCl(g) + I2(g) Mechanism B: H2(g) + ICl(g) HCl(g) + HI(g); slow HI(g) + ICl(g) HCl(g) + I2(g); fast Which of the above mechanism(s) can be consistent with the given information about the reaction?

1. A and B both
2. Neither A nor B
3. A only
4. B only

Consider the reaction : N2(g) + 3H2(g) 2NH3(g) The equality relationship between d[NH3]dt and - d[H2]dt is

1. d[NH3]dt = - d[H2]dt
2. d[NH3]dt = - 13 d[H2]dt
3. + d[NH3]dt = - 23 d[H2]dt
4. + d[NH3]dt = - 32 d[H2]dt

For the reaction, 2A + B 3C + D, which of the following does not express the reaction rate?

1. - d[A]2dt
2. - d[C]3dt
3. - d[B]dt
4. d[D]dt

The rate of reaction between two reactants A and B decreases by a factor of 4 if the concentration of reactant B is doubled. The order of this reaction with respect to reactant B is

1. 2
2. -2
3. 1
4. -1

For a first order reaction A B the reaction rate at reactant concentration of 0.01 M is found to be 2.0 10-5 mol L-1 s-1. The half-life period of the reaction is

1. 30 s
2. 220 s
3. 300 s
4. 347 s

The rate of a first order reaction is 1.5 10-2 mol L-1 min-1 at 0.5 M concentration of the reactant. The half-life of the reaction is

1. 0.383 min
2. 23.1 min
3. 8.73 min
4. 7.53 min

The temperature dependence of rate constant (k) of a chemical reaction is written in terms of Arrhenius equation, k = A e-E*/RT. Activation energy (E*) of the reaction can be calculated by plotting

1. k vs T
2. k vs 1 T
3. log k vs 1T
4. log k vs 1 T