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NEET 2020
Exam
NEET
Year
2020
Subject
Chemistry
Chapter
Chemical Kinetics

NEET 2020 · Chemistry · Chemical Kinetics

The rate constant for a first order reaction is 4.606 × 10 ^ – 3 s...

The rate constant for a first order reaction is 4.606×10–3s–14.606 \times {10}^{– 3}{s}^{– 1}. The time required to reduce 2.0g2.0g of the reactant to 0.2g0.2g is :

Options

  1. A200s200s
  2. B500s500s
  3. C1000s1000s
  4. D100s100s

Correct answer

B. 500s500s

Step-by-step solution

k=4.606×10−3s−1k = 4 . 606 \times {10}^{- 3}{s}^{- 1}

k=2.303tlogC∘Ctk = \dfrac{2 . 303}{t}log\dfrac{{C}_{∘}}{{C}_{t}}

where C∘{C}_{∘}= initial concentration

Ct{C}_{t}= concentration after time t

k=2.303tlog⁡1020.2k = \dfrac{2 . 303}{t}\log_{10}\dfrac{2}{0 .2}

4.606×10−3×t=2.303×log⁡104 . 606 \times {10}^{- 3} \times t = 2 . 303 \times \log 10

t=10002=500st = \dfrac{1000}{2} = 500s

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