Chemistry Aldehydes & Ketones NUMS 2019
PMDC Verified Question 56 of 94
Hybridization of carbon in \( -CHO \) group is:
A
sp
B
\( sp^2 \)
C
\( sp^3 \)
D
dsp
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: \( sp^2 \)
Concept:

Hybridization is determined by counting the number of electron domains (sigma bonds and lone pairs) around an atom.

Solution:

  • In the formyl group (\( -CHO \)), the central carbon atom is double-bonded to an oxygen atom and single-bonded to a hydrogen atom and the rest of the R-group.


  • This gives the carbon atom three electron domains (three regions of electron density).


  • To accommodate three domains, one s-orbital mixes with two p-orbitals to form three \( sp^2 \) hybridized orbitals, leaving one unhybridized p-orbital to form the \( \pi \) bond with oxygen.


  • The geometry is trigonal planar with bond angles of approximately 120°.


Why other options are incorrect:

\( sp^3 \) hybridization occurs in single-bonded carbons (tetrahedral). \( sp \) hybridization occurs with triple bonds or two consecutive double bonds (linear).

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