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
Answer the following in brief.
What is a zeroth-order reaction?
Answer the following in brief.
Give one example and explain why it is pseudo-first-order.
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 ______.
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?
For a first order reaction \[\ce{A ->Product}\] with initial concentration x mol L−1, has a half life period of 2.5 hours. For the same reaction with initial concentration `("x"/2)` mol L−1 the half life is
Write the rate law for the following reaction.
A reaction that is `3/2` order in x and zero order in y.
Write the rate law for the following reaction.
A reaction that is second order in NO and first order in Br2.
The integrated rate law is a direct relationship between ____________ and ____________.
A first order reaction has rate constant 1 × 10−2 s−1. What time will, it take for 20 g or reactant to reduce to 5 g?
A reaction that is of the first order with respect to reactant A has a rate constant 6 min−1. If we start with [A]0 = 0.5 mol dm−3, when would [A] reach the value 0.05 mol dm−3?
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 ____________.
What is the order of reaction if the unit of rate constant (k) is mol dm−3 s−1?
For the first order reaction, plot of log10 [A]t against time 't' is a straight line with a negative slope equal to ____________.
Half-life period of a first order reaction, \[\ce{A -> product}\] is 3.0 hours. What is the value of rate constant?
In the reaction \[\ce{2SO2 + O2 -> 2SO3}\] the rate of appearance of SO3 is 4 × 10−4 M/s, the rate of disappearance of O2 is ____________.
Reaction given below follows first order kinetics:
\[\ce{2N2O2 -> 4NO2 + O2}\]
Calculate the rate constant of reaction if concentration of N2O2 is 0.05 M and rate of reaction is 1.5 × 10−6 mol L−1 s−1?
For a zero order reaction, the plot of [A]t vs t is linear. The slope of the line is equal to ____________.
The rate of formation of B at time t for reaction \[\ce{2A -> 3B}\] is equal to ____________.
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 ____________.
0.0210 M solution of N2O5 is allowed to decompose at 43°C. How long will it take to reduce to 0.0150 M?
(Given k = 6.0 × 10−4 sec−1)
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 ________.
Which is the unit of rate constant for the first-order reaction if time is expressed in seconds?
The integrated rate law is a direct relationship between time and ______
The rate constant for a first order reaction is 7.0 × 10-4 s-1. If initial concentration of reactant is 0.080 M, what is the half-life of reaction?
What are integrated rate laws?
