H2 and Cl2 do not react in the dark, but in the presence of light a vigorous reaction is initiated due to the formation of:
Correct answer: B. Chlorine free radical
- A. Hydrogen free radical
- B. Chlorine free radical
- C. Hydrogen chloride molecule
- D. Both hydrogen and chlorine free radicals
Explanation
To break the covalent bond between two chlorine atoms, photons of ultraviolet rays are required. There is no such requirement for breaking the bond between hydrogen atoms, hence the answer is B.
This question appeared on the NUMS 2016 paper, which you can sit online with every answer explained.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? [email protected]
About Free Radical Substitution
Free radical substitution explains how alkanes react with halogens under ultraviolet light or heat through initiation, propagation and termination steps. The mechanism involves homolytic bond fission and radical intermediates, while product formation depends on the relative stability of radicals and differs from ionic substitution.
Practise Chemistry of Hydrocarbons
1,091 free Chemistry of Hydrocarbons 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 Free Radical Substitution questions
Which of the following represents the equation for the reaction between ethane and chlorine in the presence of UV radiation?
Which one of the following free radical is most stable?
The reaction mechanism of alkanes with halogens is known as;
Which of the following Halogen reacts fast with alkanes in substitution reactions?
Which of the following are products of the following reaction in the presence of sunlight? CH4+Cl2→ ?
Free radical reactions take place in the presence of _?