Question

Which of the following has ${sp}^2$-hybridisation?

• A. $C_2{H}_6$
• B. ${C_2{H}_5}^{-}$
• C. $B{eCl}_2$
• D. $C_2{H}_2$

Answer 1

Answer: (B)

${C_2{H}_5}^{-}$

In $C_2{H}_6$, both carbons have $s{p}^3$ hybridisation.

In $C_2{H_5}^{-}$, both carbons have $s{p}^2$ hybridisation.

In $s{p}^2$ hybridization, one $s$ orbital and two $p$ orbitals hybridize to form three $s{p}^2$ orbitals, each consisting of 33% $s$ character and 67% $p$ character. This type of hybridization is required whenever an atom is surrounded by three groups of electrons.

In $BeC{l}_2$ $(Cl-Be-Cl)$, beryllium has $sp$ hybridisation.

In $C_2{H}_2$, both carbons have $sp$ hybridisation.

Hence, option B is correct.