Question

Which of the following combination of orbitals are associated with the lowest bond energy?

• A. $s{p}^3-s$
• B. $s{p}^3-s{p}^2$
• C. $s{p}^2-s$
• D. $s{p}^3-s{p}^3$

Answer 1

The correct option is D $s{p}^3-s{p}^3$

Amount of energy required for breaking of a bond is called as $bond$ $energy$.

We can calculate bond energy on the basis of percentage of s character. Higher the percentage of s character lesser will be the bond length. We need more energy to break a bond when atoms are closely held and vice versa.

In $s{p}^3-s$,

percentage s character 25%+100% $=$ 125%

In $s{p}^3-s{p}^2$,

percentage s character 25%+33.33% $=$ 58.33%

In $s{p}^2-s$,

percentage s character 33.33%+100% $=$133.33%

In $s{p}^3-s{p}^3$,

percentage s character 25%+25% $=$50%

As $s{p}^3-s{p}^3$ has the least percentage of s character, least will be the bond energy.

Hence, answer is $s{p}^3-s{p}^3$