Consider the molecules CH4, NH3 and H2O. Which of the given statement ...
Introduction:
The given question is related to the bond angles in the molecules CH4 (methane), NH3 (ammonia), and H2O (water). We need to determine which of the given statements is false.
Explanation:
To answer the question, let's analyze each statement one by one:
a) The H-C-H bond angle in CH4 is larger than the H-N-H bond angle in NH3:
- In CH4, the central carbon atom is surrounded by four hydrogen atoms. The molecule has a tetrahedral shape, and all the bond angles are approximately 109.5°.
- In NH3, the central nitrogen atom is surrounded by three hydrogen atoms. The molecule has a pyramidal shape, and the bond angle is approximately 107°.
- Therefore, the H-C-H bond angle in CH4 is larger than the H-N-H bond angle in NH3, making statement (a) true.
b) The H-C-H bond angle in CH4, the H-N-H bond angle in NH3, and the H-O-H bond angle in H2O are all greater than 90°:
- In CH4, NH3, and H2O, all the bond angles are greater than 90°.
- Therefore, statement (b) is true.
c) The H-O-H bond angle in H2O is larger than the H-C-H bond angle in CH4:
- In H2O, the central oxygen atom is surrounded by two hydrogen atoms. The molecule has a bent or V-shaped structure, and the bond angle is approximately 104.5°.
- In CH4, all four hydrogen atoms are bonded to the central carbon atom, resulting in a tetrahedral shape with bond angles of approximately 109.5°.
- Therefore, the H-O-H bond angle in H2O is smaller than the H-C-H bond angle in CH4, making statement (c) false.
d) The H-O-H bond angle in H2O is smaller than the H-N-H bond angle in NH3:
- In H2O, the H-O-H bond angle is approximately 104.5°.
- In NH3, the H-N-H bond angle is approximately 107°.
- Therefore, the H-O-H bond angle in H2O is smaller than the H-N-H bond angle in NH3, making statement (d) true.
Conclusion:
From the analysis, we can conclude that statement (c) is false. The H-O-H bond angle in H2O is smaller than the H-C-H bond angle in CH4.
Consider the molecules CH4, NH3 and H2O. Which of the given statement ...
The H-O-H bond angle in H
2O is larger than the H-C-H bond angle in CH
4.
According to VBT: lone pair-lone pair repulsion is more than a bond pair -lone pair repulsion.
As the number of lone pair of electrons on central element increases, repulsion between that lone pair of electrons increases and therefore, bond angle decreases.
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