Bond dissociation energy is the energy required to break a bond, and it depends on the stability of the bond. In the case of C-H bonds, the following factors affect their bond dissociation energy:
Aromatic C-H bond (I): The C-H bond in an aromatic compound is stabilized by resonance and the delocalization of electrons in the aromatic ring. This results in a relatively high bond dissociation energy.
Aliphatic C-H bond (II): The C-H bond in a typical aliphatic compound (like an alkane) is weaker compared to the C-H bond in an aromatic system because there is no such resonance stabilization.
Thus, the bond dissociation energy will be moderate.
C-H bond in a cyclopropane-like structure (III): The C-H bond in a strained structure like cyclopropane is weaker due to the angle strain, making it easier to break. Hence, this bond has the lowest bond dissociation energy.
Thus, the correct order of bond dissociation energy is II>I>III.
A hydrocarbon which does not belong to the same homologous series of carbon compounds is
A sphere of radius R is cut from a larger solid sphere of radius 2R as shown in the figure. The ratio of the moment of inertia of the smaller sphere to that of the rest part of the sphere about the Y-axis is :
A constant voltage of 50 V is maintained between the points A and B of the circuit shown in the figure. The current through the branch CD of the circuit is :