A first order reaction takes 40 min for | Class 12 Chemistry Chapter Chemical Kinetics, Chemical Kinetics NCERT Solutions

Q19.

A first order reaction takes 40 min for 30% decomposition. Calculate t1/2.

For a first order reaction,

t = 2.303/k Log [R] º / [R]

k = 2.303/40min  Log 100 / 100-30

= 2.303/40min  Log 10 / 7

= 8.918 x 10-3 min-1

Therefore, t1/2 of the decomposition reaction is

t1/2 = 0.693/k

0.693 / 8.918 x 10-3  min

= 77.7 min (approximately)

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Important Questions & Answers

What is the correct answer to: A first order reaction takes 40 min for 30% decomposition. Calculate t1/2.?

For a first order reaction,

t = 2.303/k Log [R] º / [R]

k = 2.303/40min  Log 100 / 100-30

= 2.303/40min  Log 10 / 7

= 8.918 x 10-3 min-1

Therefore, t1/2 of the decomposition reaction is...

How do you solve A first order reaction takes 40 min for 30% decomposition. Calculate t1/2. step by step?

Step-by-step explanation:
• For a first order reaction,

• t = 2
• 303/k Log [R] º / [R]

Why is this answer important for exams?

This question is important because it tests key concepts from the NCERT syllabus and is frequently asked in CBSE exams.

Which NCERT concept is used in this question?

This question is based on core NCERT concepts explained in the chapter and should be revised thoroughly before exams.

What common mistakes should be avoided in this question?

Students often lose marks by skipping steps, writing incomplete explanations, or misunderstanding keywords used in the question.

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Student Discussion

Gitanjali
Class · · , · Jul 28, 2019
Thanks very useful for me
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Babu Rabha
Class · · , · Jul 27, 2019
thanks
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Sugandhi
Class · · , · May 21, 2019
0.693 from where or it is constant for all numericals
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Mahesh
Class · · , · Mar 30, 2019
Tqqq madam
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ikshit
Class · · , · Dec 27, 2018
great
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Aditya
Class · · , · Dec 24, 2018
Awesome
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