The rate constant of a radioactive substance is . The value of half-life will be :
1. 0.05 years
2. 0.17 years
3. 0.26
4. 1.6 years
The rate constant for a first-order reaction is . The time required to reduce 2.0 g of the reactant to 0.2 g will be:
1. | 200 s | 2. | 500 s |
3. | 1000 s | 4. | 100 s |
The graph that represents a first-order reaction is:
1. | 2. | ||
3. | 4. |
The half-life period for a first-order reaction is 20 minutes. The time required to change the concentration of the reactants from 0.08 M to 0.01 M will be:
1. | 20 minutes | 2. | 60 minutes |
3. | 40 minutes | 4. | 50 minutes |
The half-life of 92U238 against \(\alpha\)-decay is 4.5 × 109 year. The time taken in a year for the decay of the 15/16 part of this isotope will be:
1.
2.
3.
4.
The rate constant of a first-order reaction is\(4 \times 10^{-3} \mathrm{sec}^{-1}.\) At a reactant concentration of \(0.02~\mathrm{M},\) the rate of reaction would be:
1. | \(8 \times 10^{-5} \mathrm{M} ~\mathrm{sec}^{-1} \) | 2. | \(4 \times 10^{-3} \mathrm{M} ~\mathrm{sec}^{-1} \) |
3. | \(2 \times 10^{-1} \mathrm{M}~ \mathrm{sec}^{-1} \) | 4. | \(4 \times 10^{-1} \mathrm{M}~ \mathrm{sec}^{-1}\) |
The half-life time for the decomposition of a substance dissolved in is 2.5 hours at C. The amount of substance that will be left after 10 hours if the initial weight of the substance is 160 gm is:
1. | 20 gm | 2. | 30 gm |
3. | 40 gm | 4. | 10 gm |
For a reaction of the type 2A + B 2C, the rate of the reaction is given by . When the volume of the reaction vessel is reduced to th of the original volume, the rate of reaction changes by a factor of -
1. 0.25
2. 16
3. 64
4. 4
For the elementary reaction M N, the rate of disappearance of M increases by a factor of 8 upon doubling the concentration of M. The order of the reaction with respect to M will be:
1. 4
2. 3
3. 2
4. 1
If ‘a’ is the initial concentration of a substance which reacts according to zero-order kinetics and k is the rate constant, the time for the reaction to go to completion will be:
1. | a/k | 2. | 2/ka |
3. | k/a | 4. | Infinite |