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 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 _______.
The elementary reaction \[\ce{O3_{(g)} + O_{(g)} -> 2O2_{(g)}}\] 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 _______.
Write four key points about order of reaction.
Define order of reaction with suitable examples.
For the reaction 2A + B → C, rate of disappearance of A 0.076 mol s –1.
- What is the rate of formation of C?
- What is the rate of consumption of B?
- What is the rate of the overall reaction?
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 ____________.
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 order of the reaction occurring by following mechanism should be:
(i) \[\ce{A2 + B2 -> AB2 + A (slow)}\]
(ii) \[\ce{A + B2 -> AB2 (fast)}\]
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?
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?
The reaction \[\ce{A + B -> P}\], is second order in A and first order in B. What is the rate law for the reaction?
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?
Molarity of H2SO4 is 18 M. Its density is 1.8 g/ml. Hence molality is ______.
The correct order of raaii of F, F-, O and O2- is ______.
The rate constant of a reaction ______.
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.
The rate constant for a first-order reaction whose half-life is 480 seconds is ______.
`t_(1/4)` can be taken as the time taken for the concentration of a reactant to drop to `3/4` of its initial value. If the rate constant for a first order reaction is k, the `t_(1/4)` can be written as ______.
