Chemistry Chemical Bonding SET 2019
PMDC Verified Question 70 of 102
What is the shape of ammonia \( \text{NH}_3 \) molecule?
A
Pyramidal
B
Linear
C
Tetrahedral
D
Trigonal planar
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: Pyramidal
Concept:

The geometry of ammonia is defined by \( \text{sp}^3 \) hybridization with one lone pair.

Formula:

$$ \text{Type} = \text{AB}_3\text{E} \implies \text{Trigonal Pyramidal} $$

Solution:

  • Nitrogen has 5 valence electrons. It uses 3 to bond with Hydrogen atoms, leaving 1 lone pair.


  • The 4 electron domains arrange tetrahedrally to minimize repulsion, but the presence of the lone pair makes the observable molecular shape trigonal pyramidal.


Why other options are incorrect:

  • Option B: Occurs in \( \text{sp} \) hybridized molecules without distorting lone pairs.
  • Option C: Describes the electron domain geometry, but the molecular shape (excluding the invisible lone pair) is pyramidal.
  • Option D: Occurs in \( \text{sp}^2 \) molecules (like \( \text{BF}_3 \)) with no lone pairs.

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