List of top Chemistry Questions on Half life asked in KEAM

A first order reaction is 75% completed in 1000 s at 300 K. What is its half-life period at 300 K?

What is the half life period of the first order reaction whose rate constant is \(2.31 \times 10^{- 1} \mathrm{~s}^{- 1}\)

The rate constant of a first order reaction is \(231\times10^{-5}\ s^{-1}\). How long will 4 g of this reactant reduce to 2 g?

The half-life of \( _{43}\text{Tc}^{99} \) is 6 hours. If 12 mg of \( _{43}\text{Tc}^{99} \) is injected to a patient, after 24 hours how much Tc will be left in the patient’s body? (A) 0 mg

The half-life period of a first order reaction having rate constant $k = 0.231 \times 10^{-10}$ s$^{-1}$ will be}