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
Advertisements
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 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 _____________.
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 _____________.
Choose the most correct option.
For an endothermic reaction, X ⇌ Y. If Ef is the activation energy of the forward reaction and Er that for the reverse reaction, which of the following is correct?
Answer the following in brief.
For the reaction 2A + B → products, find the rate law from the following data.
| [A]/M | [B]/M | rate/M s-1 |
| 0.3 | 0.05 | 0.15 |
| 0.6 | 0.05 | 0.30 |
| 0.6 | 0.2 | 1.20 |
The rate law relates to the rate of a chemical reaction in terms of _______.
Order of reaction for which unit of rate constant is mol dm–3 s–1 is _______.
For the reaction \[\ce{2NO_{(g)} + 2H_{2(g)} -> N_{2(g)} + 2H2O_{(g)}}\],
The rate law is, rate = k[NO]2 [H2].
What is the overall order of reaction?
Write four key points about order of reaction.
A reaction occurs in the following steps:
Step 1: \[\ce{NO_{2(g)} + F_2 -> NO2F_{(g)} + F_{(g)}}\] (slow)
Step 2: \[\ce{F_{(g)} + NO_{2(g)} -> NO_2F}\] (Fast)
- Write the equation of overall reaction.
- Write the rate law.
- Identify reaction intermediate.
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:
For the reaction, \[\ce{N2(g) + 3H2(g) -> 2NH3(g); \Delta H}\] is equal to ______.
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 hypothetical reaction \[\ce{A + B -> C}\], it is found that doubling the concentration of A increases the rate by 8 times and doubling the concentration of B increases the rate by 4 times. The overall order of the reaction is ____________.
Select the rate law that corresponds to the data shown for the following reaction:
\[\ce{A + B -> C}\]
| 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 rate law for the reaction \[\ce{A + B + C -> Product}\] is expressed as Rate = k[A]2 [B]1 [C]0. What is the overall order of the reaction?
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 ____________.
The rate law for the reaction \[\ce{2NO_{(g)} + O2_{(g)} -> 2NO2_{(g)}}\] is rate = k[NO]2 [O2] , then which among the following statement is correct?
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?
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 \[\ce{4NH3 + 5O2 -> 4NO + 6H2O}\], the rate of disappearance of NH3 is 3.6 × 10-3 M/s. What is the rate of formation of water?
Which of the following unit is used to express the rate of a reaction?
The correct order of raaii of F, F-, O and O2- is ______.
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.
For the reaction A + B → P.
If [B] is doubled at constant [A], the rate of reaction doubled. If [A] is triple and [B] is doubled, the rate of reaction increases by a factor of 6. Calculate the rate law equation.
For the reaction 2A + B → A2B find the rate of decrease of [B].
