Question

The dipole moment of HBr is 2.60D and the interatomic spacing is 1.41 pm. What is the percentage of ionic character of HBr?
A.0.12
B.12
C.1.2
D.None of the above

Answer 1

Hint: A bond's percent ionic character is the amount of electron sharing between two atoms; limited electron sharing corresponds with a high percent ionic character.

Complete step by step answer:
Before we move forward with the solution of this question, let us understand some basic important concepts.
HBr is an ionic solid. So, when placed in an aqueous solution, it dissociates into ions. The ions thus formed are: \[{H^ + }\] and \[B{r^ - }\] . This means that the hydrogen ion has a charge of (-1), which means it has the charge equivalent of a proton. On the other hand, the bromine ion has a charge equivalent of an electron. Since charges of both electron and proton are the same but of opposite natures, we will consider the magnitude of the value, i.e. \[1.6 \times {10^{ - 19}}\] C.
Now, the dipole moment of a compound can be calculated using the following formula:
Dipole moment = (charge) (distance between the charges)
Dipole moment = ( \[1.6 \times {10^{ - 19}}\] C) (141 pm)
Dipole moment = ( \[1.6 \times {10^{ - 19}}\] C) ( \[141 \times {10^{ - 12}}\] m)
Dipole moment = \[22.56 \times {10^{ - 30}}\] Cm
Now, we have been asked to calculate the percentage ionic character of the given compound. Ionic character of a compound is basically the ratio of the experimentally found dipole moment of the compound to the theoretical dipole moment.
Hence, this can be represented mathematically as:
ionic character \[ = \dfrac{{\exp erimental\,\,dipole\,\,moment}}{{theoretical\,\,dipole\,\,moment}}\]
ionic character \[ = \dfrac{{2.6 \times {{10}^{ - 30}}}}{{22.56 \times {{10}^{ - 30}}}}\]
ionic character = 0.1152
hence,
% ionic character = ionic character x 100
% ionic character = (0.1152) (100)
% ionic character \[ = 11.52\% \]
This value can be approximated to be \[12\% \]

Hence, Option B is the correct option.

Note:

Note:
An arrangement of two equal and opposite charges separated by a finite distance is called an electric dipole. Electric dipole moment of an electric dipole is defined as the product of either of its charges and the length of the dipole.