Which of the following compounds possesses the C-H bond with the lowest bond dissociation

⇦

⇨

Which of the following compounds possesses the C-H bond with the lowest bond dissociation energy?

Options

(a) Toluene
(b) Benzene
(c) n-Pentane
(d) 2,2-Dimethylpropane

Correct Answer:

Toluene

Explanation:

Structure of Toluene:

Toluene (C₆H₅CH₃) = 85 kcal/mol

Benzene (C₆H₆) = 110 kcal/mol

n-Pentane (CH₃CH₂CH₂CH₃ ) = 98 kcal/mol

2, 2-Dimathylpropane = 92 kcal/mol

Toluene has the lowest C – H bond dissociation energy compare to other three.

Toluene is a Tertiary free radical. Bond Dissociation Energy of C-H bonds decreases as we go from methyl to primary to secondary to tertiary. They are easier to break since homolytic bond cleavage results in a more stable radical. 

Related Questions:

1. The best coagulant for the precipitation of Fe(OH)₃ is
2. Surface tension vanishes at
3. D(+)-glucose reacts with hydroxyl amine and yields an oxime.
4. Reaction of solid KMnO₄ ith conc.H₂SO₄ produces manganese heptoxide (Mn₂O₇) in
5. The combustion enthalpies of carbon , hydrogen and methane are -395.5 kJ mol⁻¹

Topics: Chemical Bonding and Molecular Structure (86)
Subject: Chemistry (2512)

---

Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score

18000+ students are using NEETLab to improve their score. What about you?

Solve Previous Year MCQs, Mock Tests, Topicwise Practice Tests, Identify Weak Topics, Formula Flash cards and much more is available in NEETLab Android App to improve your NEET score.

---

Share this page with your friends