If the half-life (t1/2) for a first order reaction is 1 minute, then the time required for 99.9% completion of the reaction is closest to :

NEET UG 2025 · Chemistry · Question 56

NEET 2025 Chemistry, question 56

Question 56 of the NEET 2025 paper (code 45) is a Chemistry question from Chemical Kinetics. Its idea, First Order 99.9% Completion Shortcut, was asked only this once in NEET 2017–2026. The NTA final answer key gives option 4.

Updated 2026-10-08

Q56 · Chemistry

t_{1/2}

1 2 minutes 2 4 minutes 3 5 minutes 4 10 minutes Official answer

Official answer: option 4 · NTA final answer key

Same idea

The only question on First Order 99.9% Completion Shortcut

No other NEET paper from 2017–2026 tested this exact idea.

First Order 99.9% Completion Shortcut: every question and how it was framed

The chapter

Chemical Kinetics in ten years of NEET

21 questions from 2017–2026, asked in 10 of 10 papers, about 2.0 a paper. Chemical Kinetics alone had 21.

Chapter analysis Study this chapter Practise this chapter

The only question on First Order 99.9% Completion Shortcut

Chemical Kinetics in ten years of NEET

Chemical Kinetics: questions per paper