Question

In which of the following molecules/ions, are all the bonds not equal?

• A. NF\(_3\)
• B. NH\(_4^+\)
• C. AgCl
• D. CH\(_4\)

Hint:

In molecules with lone pairs on the central atom (like NF\(_3\)), the bonds may not be equal due to differences in electron repulsion. In symmetrical molecules like NH\(_4^+\) and CH\(_4\), the bonds are equal.

Answer 1

The Correct Option is A

To determine in which molecule or ion all the bonds are not equal, let's examine each option provided:

• NF\(_3\): Nitrogen trifluoride has a trigonal pyramidal structure. Since nitrogen is more electronegative than fluorine, the N-F bonds will be polar. Due to the lone pair on nitrogen, the molecular geometry doesn't allow for symmetric distribution of electrons, leading to unequal bond angles.
• NH\(_4^+\): The ammonium ion has a tetrahedral shape. All the N-H bonds are equivalent due to uniform tetrahedral geometry, resulting in equal bond lengths and angles.
• AgCl: Silver chloride is an ionic compound consisting of Ag\(^+\) and Cl\(^-\) ions, and thus does not have multiple bonds to compare.
• CH\(_4\): Methane has a perfect tetrahedral shape. All C-H bonds are identical due to symmetrical distribution, which makes all bonds equal.

In conclusion, NF\(_3\) is the molecule where all the bonds are not equal due to the asymmetric shape and the presence of a lone pair on the nitrogen atom, affecting bond angles and lengths.