For 3rd order reaction the hhalf life is inversely proportional to initial concentration of reactants__________________?

Correct answer: B. Square

  • A. Single
  • B. Square
  • C. Cube
  • D. Raise to power four

Explanation

For a single-reactant third-order reaction, the half-life varies inversely with the square of the initial reactant concentration, written as t1/2 proportional to 1/[A]0^2. Therefore, doubling the initial concentration makes the half-life one-fourth as large. Students may choose c by matching the power of the reaction order directly, but the half-life relation has the square of the concentration in the denominator for a third-order reaction.

Written and checked by , M.Phil ChemistryLast updated
Report an error

The more specific you are, the faster it gets fixed. A source beats an opinion.

Prefer email? [email protected]

About Order of Reaction

Reaction order shows how the rate depends on the concentration of each reactant, as expressed in the rate law. Coverage includes zero, first and second-order reactions, integrated rate equations, half-life, units of rate constants and the distinction between overall order and molecularity.

Practise Reaction Kinetics

573 free Reaction Kinetics MCQs from Chemistry, each with the correct answer and an explanation. Unlimited attempts, no account needed.

Discussion

Stuck on an option, or know a faster way to get there? Ask or explain it here.

No comments yet. Be the first to explain this one.

Exams that ask Chemistry questions like this

Chemistry is on 14 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.

More Order of Reaction questions