Chemistry Chemical Bonding MDCAT 2019
PMDC Verified Question 71 of 102
Which one of the following molecules has \( \text{sp}^3 \) hybridization?
A
\( \text{CH}_4 \)
B
\( \text{C}_2\text{H}_2 \)
C
\( \text{C}_2\text{H}_4 \)
D
\( \text{CO}_2 \)
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: \( \text{CH}_4 \)
Concept:

Hybridization is determined by the number of sigma bonds and lone pairs on the central atom.

Formula:

$$ \text{Steric Number} = (\sigma \text{ bonds}) + (\text{lone pairs}) $$

Solution:

  • In methane (\( \text{CH}_4 \)), Carbon forms 4 sigma bonds and has 0 lone pairs.


  • Steric number = 4, which perfectly corresponds to \( \text{sp}^3 \) hybridization (mixing one s and three p orbitals).


Why other options are incorrect:

  • Option B: Ethyne (\( \text{C}_2\text{H}_2 \)) has a triple bond, making its carbons \( \text{sp} \) hybridized.
  • Option C: Ethene (\( \text{C}_2\text{H}_4 \)) has a double bond, making its carbons \( \text{sp}^2 \) hybridized.
  • Option D: Carbon dioxide (\( \text{CO}_2 \)) has two double bonds on the central carbon, making it \( \text{sp} \) hybridized.

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