The strength of a covalent bond depends upon the size of the atoms and the bond order. In general short bonds are strong bonds. 1. For each pair of covalently bonded atoms, choose the one expected to have the higher bond energy. (A) C≡C (B) C=C ... (A, B) (C) C=N (D) C-N ... (C, D)

Bond energy of (A) C≡C > (B) C=C

and, (C) C=N > (D) C-N

Explanation:

Bond energy refers to the amount of energy required to break a bond or the energy released when a bond is formed. Bond energy of a covalent bond suggests the bond strength of the chemical bond and depends on the bond length and bond order of the chemical bond.

The bond energy of a chemical bond increases with the bond order and decreases with the bond length. As, length of a bond decreases with increase in the bond order.

First pair: (A) C≡C (B) C=C

The bond order of C≡C - 3, the bond order of C=C - 2

Since the bond order: C≡C > C=C

Bond length: C≡C < C=C

Therefore, bond energy of (A) C≡C > (B) C=C

Second pair: (C) C=N (D) C-N

The bond order of C=N - 2, the bond order of C-N - 1

Since the bond order: C=N > C-N

Bond length: C=N < C-N

Therefore, bond energy of (C) C=N > (D) C-N