Asked in Premeth Test 23 — Chemical Kinetics and Chemical Equilibrium (25 March 2025) 2025

In the rate equation R=k[A]a [B]b, the order of the reaction is _.

Correct answer: D. a + b

  • A. ax b
  • B. a - b
  • C. b - a
  • D. a + b

Explanation

In any chemical reaction, we can have more than two reactants reacting and giving some products. In a rate equation, we multiply the concentration of each reactant used and they all are raised to some powers which are their orders e.g [CH3CH2OH]2. The 2 on ethanol shows its order. So if you want to calculate the order of overall reaction we need to sum up the orders of every reactant. Hence the answer is D.

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