Question

List the bonds P-Cl,P-F,O-F, and Si - F from least polar to most polar.

Short answer

The molecules are arranged in increasing order of polarity.

$\mathrm{O}-\mathrm{F}<\mathrm{P}-\mathrm{Cl}<\mathrm{P}-\mathrm{F}<\mathrm{Si}-\mathrm{F}$

Step-by-step solution

Write the electro negativity values:

We know, while moving across the periodic table, electronegativity of elements increases from left to right. While moving down a group electronegativity decreases. Polarity is measured by dipole moment. Dipole moment is proportional to the electronegativity difference between two elements. The electronegativity values of some specific elements are given below.

$$\begin{gathered} \mathrm{P}=2.19 \\ \mathrm{Cl}=3.16 \\ \mathrm{F}=3.98 \\ \mathrm{O}=3.44 \\ \mathrm{Si}=1.9 \end{gathered}$$

Calculate electro negativity differences and relate it with polarity:

The electronegativity difference is calculated for each molecule. Higher the electronegativity difference , higher will be the dipole moment.

$$\begin{gathered} \mathrm{P}-\mathrm{Cl}=3.16-2.19=0.97 \\ \mathrm{P}-\mathrm{F}=3.98-2.19=1.79 \\ \mathrm{O}-\mathrm{F}=3.98-3.44=0.28 \\ \mathrm{Si}-\mathrm{F}=3.98-1.9=2.08 \end{gathered}$$

So the order will be$\mathrm{O}-\mathrm{F}<\mathrm{P}-\mathrm{Cl}<\mathrm{P}-\mathrm{F}<\mathrm{Si}-\mathrm{F}.$