Advertisements
Advertisements
प्रश्न
What is half life of first order reaction if time required to decrease concentration of reactants from 0.8 M to 0.2 M is 12 hours?
Advertisements
उत्तर १
Given: [A]0 = 0.8 M, [A]t = 0.2 M, t = 12 hours
To find: Half life of reaction (t1/2)
Formulae:
- k = `2.303/"t" log_10 (["A"]_0)/(["A"]_"t")`
- `"t"_(1/2) = 0.693/"k"`
Calculation: Substituting given value in
k = `2.303/"t" log_10 (["A"]_0)/(["A"]_"t")`
k = `2.303/(12 "hr") log_10 0.8/0.2`
= `2.303/(12 "hr") log_10 (4)`
= `2.303/(12 "hr") xx 0.6020`
= Antilog10 (log10 2.303 + log10 0.6020 − log10 12)
= Antilog10 (0.3623 + `bar(1).7796` − 1.0792 )
= Antilog10 `(bar(1).0627 )`
= 0.1115 hr–1
`"t"_(1/2) = 0.693/"k" = 0.693/(0.1155 "hr"^-1)` = 6 hr
उत्तर २
Concentration is reduced to 25%. It means it takes two half-lives to decrease the concentration of reactant from 0.8 M to 0.2 M in first-order reaction. Hence, half-life of the reaction is 12/2 = 6 hours.
The half life of reaction is 6 hours.
APPEARS IN
संबंधित प्रश्न
Solve
The half-life of a first-order reaction is 1.7 hours. How long will it take for 20% of the reactant to react?
Solve
A first-order reaction takes 40 minutes for 30% decomposition. Calculate its half-life.
Rate constant of a reaction is 3.6 × 10–3 s–1. The order of reaction is ______.
For first order reaction, the rate constant for the decomposition of N2O5 is 6 × 10–4 s –1. The half-life period for decomposition in seconds is ______.
The rate of catalysed reaction is large than the uncatalysed reaction as _______.
Explain with the help of a potential energy diagram that the catalyst increases the rate of the reaction.
A zero-order reaction \[\ce{X -> Product}\], with an initial concentration 0.02 M has a half-life of 10 min. if one starts with concentration 0.04 M, then the half-life is
The rate constant of a reaction is 5.8 × 10−2 s−1. The order of the reaction is ____________.
If 75% of a first order reaction was completed in 60 minutes, 50% of the same reaction under the same conditions would be completed in ____________.
Write the rate law for the following reaction.
A reaction that is `3/2` order in x and zero order in y.
Give two examples for zero order reaction.
The time for half change in a first order decomposition of a substance A is 60 seconds. Calculate the rate constant. How much of A will be left after 180 seconds?
How long would it take to electroplate a spoon with 0.1 mol of silver (108 g/mol) at a constant current of 2.0 A using AgNO3?
The rate constant of a reaction has same units as the rate of reaction. The reaction is of ____________.
The rate and the rate constants of the reaction, \[\ce{A + 2B -> C + D}\] are 8 × 10−3 mol dm−3 s−1 and 2 × 10−3 s−1 respectively. The concentrations of A and B are 4 mol dm−3 each. The overall order of the reaction is ____________.
The order of the reaction for which the unit of rate constant is s−1 is ____________.
Half-life period of a first order reaction, \[\ce{A -> product}\] is 3.0 hours. What is the value of rate constant?
A first order reaction is 75% completed in 60 minutes, the time required for it's 50% completion is ____________.
The rate of formation of B at time t for reaction \[\ce{2A -> 3B}\] is equal to ____________.
A first order reaction is 50% completed in 16 minutes. The percentage of reactant that will react in 32 minutes is ____________.
The time required to decompose SO2Cl2 to half of it's initial amount is 60 minutes. Calculate rate constant for this first order reaction.
Half-life of first order reaction is 20 minutes. What is the time taken to reduce the initial concentration of the reactant to `1/10`th?
What is the unit of rate constant for the zero order reaction?
Rate constant for zero order reaction is 2 × 10-2 mol L-1 s-1. If the concentration of the reactant after 25 sec. is 0.5 M, what is the initial concentration of reactant?
For zero order reaction, when [A]t is plotted against time (t), the slope of the straight line obtained is equal to ______.
Calculate half-life of a first order reaction in minute if the rate constant is 1 × 10-3 s-1.
The half-life of first order reaction is 1.7 hour. What is its rate constant?
The half-life period for the first order reaction is 1.7 hrs. How long will it take for 20% of the reactant to disappear?
