Advertisements
Advertisements
प्रश्न
What is the half life of a first order reaction if time required to decrease concentration of reactant from 0.8 M to 0.2 M is 12 h?
विकल्प
12 h
3 h
1.5 h
6 h
उत्तर
6 h
Explanation:
`k = 2.303/t log((A_0)/(A_t))`
Where,
A0 is the initial concentration,
At is the concentration after time t,
t is the time taken.
`k = 2.303/12 log((0.8)/(0.2))`
`k = 2.303/12 log(4)`
`k = 2.303/12 2log(2)`
`k = 2.303/12 xx 0.6020`
`k = (2.303 xx 0.6020)/12`
`k = 1.384306/12`
k ≈ 0.11536 hr−1
`t_(1//2) = 0.693/k`
`t_(1//2) = 0.693/0.11536`
`t_(1//2) ≈ 6.01` h
The half-life of the first-order reaction is approximately 6 hours.
APPEARS IN
संबंधित प्रश्न
Choose the most correct option.
The order of the reaction for which the units of the rate constant are mol dm-3 s-1 is _______.
Choose the most correct option.
The rate constant for the reaction \[\ce{2N2O5_{(g)} -> 2N2O4_{(g)} + O2_{(g)}}\] is `4.98 xx 10^-4 "s"^-1`. The order of reaction is _____________.
The time required for 90% completion of a certain first-order reaction is t. The time required for 99.9% completion will be _________.
Choose the most correct option.
Slope of the graph ln[A]t versus t for first-order reaction is _________.
Choose the most correct option.
The reaction, \[\ce{3ClO- -> ClO^-3 + 2Cl-}\] occurs in two steps,
(i) \[\ce{2ClO- -> ClO^-2}\]
(ii) \[\ce{ClO^-2 + ClO- -> ClO^-_3 + Cl-}\]
The reaction intermediate is _______.
Choose the most correct option.
Rate law for the reaction, \[\ce{2NO + Cl2 -> 2NOCl}\] is rate = k[NO2]2[Cl2]. Thus of k would increase with _____________.
A First order reaction is 50% complete in 69.3 minutes. Time required for 90% completion for the same reaction is _______.
The rate constant of a first order reaction whose half-life is 480 seconds, is ____________.
For the non-stoichiometric reaction
\[\ce{2A + B -> C + D}\], the following kinetic data were obtained in three separate experiments, all at 298 K.
| Initial concentration (A) |
Initial concentration (B) |
Initial rate of formation of C (mol dm−3 s−1) |
| 0.1 M | 0.1 M | 1.2 × 10−3 |
| 0.1 M | 0.2 M | 1.2 × 10−3 |
| 0.2 M | 0.1 M | 2.4 × 10−3 |
The rate law for the formation of C is:
A gaseous hypothetical chemical equation \[\ce{2A ⇌ 4B + C}\] is carried out in a closed vessel. The concentration of B is found to increase by 5 × 10−3 mol dm−3 in 10 second. The rate of ____________.
For a chemical reaction rate law is, rate = k[A]2[B]. If [A] is doubled at constant [B], the rate of reaction ______.
Select the rate law that corresponds to the data shown for the following reaction:
| Exp. | [A] mol dm−3 |
[B] mol dm−3 |
Initial Rate mol dm−3 |
| 1. | 0.012 | 0.035 | 0.10 |
| 2. | 0.024 | 0.070 | 0.80 |
| 3. | 0.024 | 0.035 | 0.10 |
| 4. | 0.012 | 0.070 | 0.80 |
The order of the reaction occurring by following mechanism should be:
(i) \[\ce{A2 + B2 -> AB2 + A (slow)}\]
(ii) \[\ce{A + B2 -> AB2 (fast)}\]
Consider the reaction \[\ce{2A + 2B -> C + 2D}\], if concentration of A is doubled at constant [B], rate increases by a factor 4. If concentration B is doubled at constant [A] the rate is doubled. Rate law of the reaction is ____________.
In the reaction \[\ce{A + B2 -> AB + B}\], the rate of reaction is directly proportional to the concentration of A and independent on the concentration of B2. What is the rate law expression?
In the reaction, \[\ce{N2 + 3H2 -> 2NH3}\], the rate of disappearance of H2 is 0.02 Mis. The rate of appearance of NH3 is ______.
What is the order of reaction for decomposition of gaseous acetaldehyde?
What is the molecularity and order of the following reaction if rate law is, rate = k[O3][O] respectively.
\[\ce{O_{3(g)} + O_{(g)} -> 2O_{2(g)}}\]
In the reaction \[\ce{2SO_{2_{(g)}} O_{2_{(g)}} -> 2SO_{3_{(g)}}}\], the rate of disappearance of SO2 is 1.28 × 10-5 M/s. What is the rate of appearance of SO3?
For the reaction \[\ce{2A + B -> 3C + D}\], which among the following is NOT the correct rate law expression?
Write the rate law for the following reaction:
A reaction that is zero order in A and second order in B.
Write the rate law for the following reaction:
A reaction that is second order in NO and first order in Br2.
The rate constant of a reaction ______.
