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 one or two sentences.
What are the units for rate constants for zero-order and second-order reactions if time is expressed in seconds and concentration of reactants in mol/L?
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.
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 ______.
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 \[\ce{A ->Product}\] 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
The decomposition of phosphine (PH3) on tungsten at low pressure is a first-order reaction. It is because the
In a first order reaction \[\ce{x -> y}\]; if k is the rate constant and the initial concentration of the reactant x is 0.1 M, then, the half life is
Identify the order for the following reaction.
Radioactive disintegration of 92U238
The integrated rate law is a direct relationship between ____________ and ____________.
The time of completion of 90% of a first order reaction is approximately ____________.
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 ____________.
For the first order reaction, plot of log10 [A]t against time 't' is a straight line with a negative slope equal to ____________.
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 initial concentration of reactant (A) is 2 mol dm−3 for a zero order reaction \[\ce{A -> B}\]. The rate constant (k) is related to its half-life `("t"_(1//2))` by the equation:
A first order reaction is 50% completed in 16 minutes. The percentage of reactant that will react in 32 minutes is ____________.
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 first order reaction, A → B takes 100 minutes for it's 90% completion. What is the rate constant of reaction?
The expression to calculate time required for completion of zero order reaction is ______.
The integrated rate law is a direct relationship between time and ______
Which of the following is correct for a first-order reaction?
Which is the relation between half life and rate constant for a zero order?
The plot that represents the zero order reaction is:
For a first order reaction, the plot of log k against 1/T is a straight line. The slope of the line is equal to ______.
If the half-life of a first-order reaction is 10 minutes, find the time required to decrease the concentration of the reactant from 0.08 M to 0.02 M.
