List of top Chemistry Questions on Half life

For a first-order reaction \( A \rightarrow B \), the rate constant is \( 0.1 \text{ s}^{-1} \). What is the time required for \( 50\% \) completion?
The reaction \( A(g) \rightarrow P(g) + Q(g) + R(g) \) follows first-order kinetics with a half-life of \( 69.3 \) s at \( 500^{\circ}\text{C} \). Starting with pure \( A \) in a container at \( 500^{\circ}\text{C} \) and a pressure of \( 0.4 \) atm, what will be the total pressure of the system after \( 230 \) s?
A radioactive sample has a half-life of 10 days. The fraction of the initial nuclei decayed after 40 days is:
The half-life of a radioactive substance is 10 days. After 30 days, fraction remaining is:
The half-life of a first-order reaction is:
Calculate the half-life of a first-order reaction if the rate constant is \(0.693\, \text{min}^{-1}\).
A first order reaction is 75% completed in 1000 s at 300 K. What is its half-life period at 300 K?
A first order reaction is 75% completed in 6000 s. What is its half life period at the same temperature? ________.
For a reaction, \( A \to B \), rate equation is \( r = k[A]^0 \). If initial concentration of reactant is \( a \) mol dm\(^{-3}\), find the half-life time of the reaction.
Which of the following is NOT dihydric phenol?
What is half life of a first order reaction if time required to decrease concentration of reactant from 0.4 M to 0.1 M is $x$ hour?
Half-life of a first-order reaction is 20 minutes. The time taken to reduce the initial concentration of the reactant to \( \left(\frac{1}{10}\right)^{\text{th}} \) of its initial value is \( \rule{1cm}{0.15mm} \).
The first order rate constant for the decomposition of \( \text{N}_2\text{O}_5 \) is \( 6.93 \times 10^{-4}\, \text{sec}^{-1} \). Its half-life period is
What is half life of a first order reaction if time required to decrease concentration of reactant from 0.4 M to 0.1 M is $x$ hour?
Which of the following is NOT dihydric phenol?
A first order reaction has a rate constant of $6.93\times10^{-4}\ \text{s}^{-1}$ at $300\ \text{K}$. What is the half-life period of the reaction in seconds at the same temperature?
The time needed for completion of 80% is \( y \) times the half-life period of a first order reaction. What is the value of \( y \)?
What is half life of a first order reaction if time required to decrease concentration of reactant from 0.4 M to 0.1 M is $x$ hour?
What is the half life period of the first order reaction whose rate constant is \(2.31 \times 10^{- 1} \mathrm{~s}^{- 1}\)
If half life of a first order reaction is 10 minutes, find the time required to decrease concentration of reactant from $0.08 \text{ M}$ to $0.02 \text{ M}$.
What is rate constant of a first order reaction having half life \(138.6 \text{ minute}\)?
For a first order reaction, time required for 99% completion is \(x\) times the time required for 90% completion. Find \(x\).
Half life of a first order reaction is \(36\;hr\). Find out time (in hour) required for concentration of reactant to get reduced by \(90\%\).
The number of incorrect statement/s from the following is ____ .
A. The successive half lives of zero order reactions decreases with time.
B. A substance appearing as reactant in the chemical equation may not affect the rate of reaction.
C. Order and molecularity of a chemical reaction can be a fractional number.
D. The rate constant units of zero and second order reaction are mol L–1s–1 and mol–1 Ls–1 respectively.
The time required for completion of \(93.75\%\) of a first order reaction is \(x\) minutes. The half life of it (in minutes) is