Question

The dative bond is present in

• A. ${\mathrm{BF}}_3$
• B. ${\mathrm{NH}}_3$
• C. ${\mathrm{PCl}}_5$
• D. ${\mathrm{NH}}_4\mathrm{Cl}$

Answer 1

The correct option is D

${\mathrm{NH}}_4\mathrm{Cl}$

The explanation for the correct option:

Option (d) ${\mathrm{NH}}_4\mathrm{Cl}$

Dative bonding:

• Dative bonding, also known as co-ordinate bonding, is a form of covalent relationship in which electrons from the same atom are shared.
• Dative bonding examples include:

1. Ammonium ion formation
2. Ammonia boron trifluoride formation
3. Hydronium ion formation
4. Ammonium Ion Formation

• The Nitrogen atom ($\mathrm{N}$) in Ammonia (${\mathrm{NH}}_3$) gives its electron pair to the vacant orbital of the ${\mathrm{H}}^{+}$ ion, forming a co-ordinate connection between Nitrogen and ${\mathrm{H}}^{+}$ in Ammonium ion (${{\mathrm{NH}}_4}^{+}$)

• The dative bond is shown as an arrow pointing in the direction of an atom giving the lone pair to the atom receiving it

The explanation for incorrect options:

Option (a) ${\mathrm{BF}}_3$

• This option is incorrect because there is no dative bond present here.
• Instead, there is $\mathrm{p\pi }-\mathrm{d\pi }$ back-bonding

Option (b) ${\mathrm{NH}}_3$

• This compound does not have any dative bond.
• It has all three covalent bonds and a lone pair, but no dative bond.

Option (c) ${\mathrm{PCl}}_5$

• This option is incorrect as there is no dative bond.
• It has a simple structure with trigonal bipyramidal geometry as shown below:

Hence, option (d) is correct.