Question

Which bond is stronger? Briefly explain why.

Short answer

a. CH₃-Cl bond is stronger.

b. I-Br bond is stronger.

Step-by-step solution

Reason of stronger bond

A bond between two atoms becomes stronger when it is hard to break, which means when the bond is strong. If there is a huge charge separation between two atoms, the bond will be weaker and easy to break as the electron is shifted towards a certain atom and not shared by both of the atoms equally.

 Step 2: Comparison of bond strength

a. In the 1^st case, the CH₃-Br bond has longer distance than CH₃-Cl as Cl is more electronegative which it will pull more electrons towards it than Br which makes the latter bond stronger and hard to break.

b. In the 2^nd case, the I-Br bond has a longer distance than Br-Br as in the latter case, both the Br are same in size which increases its lattice energy than the former case where one atom is I is more diffused in nature. As a matter of fact, due to high lattice energy, the Br-Br bond is stronger.