Advertisements
Advertisements
प्रश्न
In a first-order reaction, the concentration of the reactant decreases from 20 mmol dm−3 to 8 mmol dm−3 in 38 minutes. What is the half-life of reaction?
Advertisements
उत्तर
Given:
[A]0 = 20 m mol dm−3,
[A]t = 8 m mol dm−3,
t = 38 min
To find:
Half-life of reaction t1/2 = ?
Formulae:
i. `k = 2.303/t log_10 [A]_0/[A]_t`
ii. t1/2 = `0.693/k`
Calculation:
Substituting given value in
`k = 2.303/t log_10 [A]_0/[A]_t`
`k = 2.303/(38 min) log_10 20/8`
= `2.303/(38 min) log_10 (2.5)`
= `2.303/(38 min) xx 0.3979`
= 0.0241 min−1
t1/2 = `0.693/k`
= `0.693/0.0241`
= 28.7 min
The half life of reaction is 28.7 min.
APPEARS IN
संबंधित प्रश्न
Answer the following in brief.
Derive the integrated rate law for the first-order reaction,
\[\ce{A_{(g)} -> B_{(g)} + C_{(g)}}\] in terms of pressure.
Solve
A first-order reaction takes 40 minutes for 30% decomposition. Calculate its half-life.
Answer the following in brief.
What are the units of the rate constant?
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?
For the reaction 2NOBr → 2NO2 + Br2, the rate law is rate = k[NOBr]2. If the rate of a reaction is 6.5 × 10–6 mol L–1 s–1, when the concentration of NOBr is 2 × 10–3 mol L–1. What would be the rate constant of the reaction?
Explain pseudo first order reaction with a suitable example.
Explain with the help of a potential energy diagram that the catalyst increases the rate of the reaction.
The rate constant of the first order reaction is 1.386 min–1. Calculate the time required for 80% reactant to decompose?
For a first-order reaction \[\ce{A -> B}\] the rate constant is x min−1. If the initial concentration of A is 0.01 M, the concentration of A after one hour is given by the expression.
The decomposition of phosphine (PH3) on tungsten at low pressure is a first-order reaction. It is because the
For a first-order reaction, the rate constant is 6.909 min−1 the time taken for 75% conversion in minutes is
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?
The rate constant of a first order reaction is 3 × 10−6 per s. If the initial concentration is 0.10 mol dm−3, the initial rate of reaction is ____________.
In a first order reaction, the concentration of the reactant, decreases from 0.8 mol dm−3 to 0.4 mol dm−3 in 15 minutes. The time taken for the concentration to change from 0.1 mol dm−3 to 0.025 mol dm−3 is ____________.
For the first order reaction, plot of log10 [A]t against time 't' is a straight line with a negative slope equal to ____________.
The time taken for 80% of a first order reaction to be complete is approximately ____________.
The half-life of a first order reaction is 6.0 hour. How long will it take for the concentration of reactant to decrease from 0.4 M to 0.12 M?
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?
A first order reaction takes 40 minutes for 30% decomposition. What is the half-life of reaction?
In a reaction \[\ce{N2_{(g)} + 3H2_{(g)} -> 2NH3_{(g)}}\], if the rate of disappearance of N2(g) is 2.6 × 10−4 M/s, the rate of disappearance of H2(g) in M/s is ____________.
A first order reaction takes 40 minutes for 30% completion. Calculate the half-life of reaction.
For the first order reaction A → B, the rate constant is 0.25 s-1, if the concentration of A is reduced to half, the value of rate constant will be ________.
A certain zero order reaction has rate constant 0.025 M s-1. What will be the concentration of reactant 'A' after 15 seconds, if initial concentration is 0.50 M?
A first order reaction, A → B takes 100 minutes for it's 90% completion. What is the rate constant of reaction?
For zero order reaction, when [A]t is plotted against time (t), the slope of the straight line obtained is equal to ______.
The expression to calculate time required for completion of zero order reaction is ______.
Which among the following reactions is an example of pseudo first order reaction?
Which of the following is correct for a first-order reaction?
Calculate the time required to decrease the concentration of reactant of first order reaction from 0.8 M to 0.1 M if rate constant is 0.1155 hour−1.
