Advertisements
Advertisements
प्रश्न
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?
उत्तर
Given: Half life (t1/2) = 1.7 hours, [A]0 = 100%, [A]t = 100 − 20 = 80%
To find: Time for 20% of reactant to react = t
Formulae:
- `"t"_(1/2) = 0.693/"k"`
- `"t" = 2.303/"K" log_10 ["A"]_0/["A"]_"t"`
Calculation: `"t"_(1/2) = 0.693/"k"`
k = `0.693/"t"_(1/2) = 0.693/(1.7 "h")` = 0.4076 h−1
t = `2.303/"k" log_10 ["A"]_0/["A"]_"t"`
= `2.303/(0.4076 "h"^-1) log 100/80`
t = `2.303/(0.4076 "h"^-1) xx 0.0969`
`= 0.5475 "h" xx (60 "min")/(1 "h")`
= 32.9 min
The time required for 20% of reaction to react is 0.5475 h or 32.9 min.
संबंधित प्रश्न
Answer the following in one or two sentences.
Write the relationships between rate constant and half-life of the first order and zeroth-order reactions.
Answer the following in brief.
Obtain the relationship between the rate constant and half-life of a first-order reaction.
What are pseudo-first-order reactions?
Answer the following in brief.
Derive the integrated rate law for the first-order reaction.
Answer the following in brief.
What are the units of the rate constant?
Derive the integrated rate law for the zeroth order reaction.
Derive an expression for the relation between half-life and rate constant for first-order reaction.
This reaction follows first-order kinetics. The rate constant at particular temperature is 2.303 × 10−2 hour−1. The initial concentration of cyclopropane is 0.25 M. What will be the concentration of cyclopropane after 1806 minutes? (log 2 = 0.3010)
Assertion: rate of reaction doubles when the concentration of the reactant is doubles if it is a first-order reaction.
Reason: rate constant also doubles.
The integrated rate law is a direct relationship between ____________ and ____________.
For first order reaction the concentration of reactant decreases from 0.2 to 0.1 M in 100 minutes. What is the rate constant of the reaction?
A first order reaction is 25% completed in 40 minutes. What is the rate constant k tor the reaction?
The rate constant of a reaction has same units as the rate of reaction. The reaction is of ____________.
The activation energy of a reaction is zero. Its rate constant at 280 K is 1.6 × 10-6 s-1, the rate constant at 300 K is ______.
What is the order of reaction if the unit of rate constant (k) is mol dm−3 s−1?
If time required to decrease concentration of reactant from 0.8 M to 0.2 M is 12 hours, the half life of this first order reaction is ____________.
The slope of a graph, log [A]t versus 't' for a first order reaction is −2.5 × 10−3 s−1. The rate constant for the reaction is ____________.
Which among the following is an example of zero order reaction?
For a first order reaction, \[\ce{A -> B}\], if [A] = 1 M and rate is 4 × 10−2 M s−1. What is the rate constant of the reaction?
The time required to decompose SO2Cl2 to half of it's initial amount is 60 minutes. Calculate rate constant for this first order reaction.
A first order reaction, A → B takes 100 minutes for it's 90% completion. What is the rate constant of reaction?
What is the unit of rate constant for the zero order reaction?
The integrated rate equation is Rt = log C0 – log Ct, then the straight-line graph is obtained by plotting.
The expression to calculate time required for completion of zero order reaction is ______.
Define the half-life of a first-order reaction.
If the rate constant for a first-order reaction is k, the time (t) required for the completion of 99% of the reaction is given by:
Half-life of a first order reaction is 30 minutes and initial concentration of reactant is 0.1 M.
What is half-life of the reaction if initial concentration of reactant is doubled?
The half-life of first order reaction is 1.7 hour. What is its rate constant?
