Q64P - Chemistry: Molecular Nature Of Matter And Change

Question

Which is the more polar bond in each of the following pairs from Problem 9.62: (a) or (b); (c) or (d); (e) or (f)?

Step-by-Step Solution

Answer

The difference in electronegativity between the two atoms that form the bond determines the bond's polarity.

Step 1: Lewis structures for covalently bonded compounds

Bonds are depicted as lines. Lone pair electrons are pairs of dots. All atoms (except H) desire eight electrons (octet rule) Typically, an atom will form one bond for each electron. Premise of the Central Atom: The central atom is the least electronegative (except hydrogen, it only has one electron)

Step 2:Difference between polar bonds in each of the subsequent pairs

$$\begin{gathered} \left(\mathrm{a}\right) \mathrm{Br} \to \mathrm{Cl} = \mathrm{\Delta EN} = 0.2 \\ \left(\mathrm{b}\right) \mathrm{F} \leftarrow \mathrm{Cl} = \mathrm{\Delta EN} = 0.8 \\ \left(\mathrm{c}\right) \mathrm{H} \to \mathrm{O} = \mathrm{\Delta EN} = 1.24 \\ \left(\mathrm{d}\right) \mathrm{Se} \to \mathrm{H} = \mathrm{\Delta EN} = 0.36 \\ \left(\mathrm{e}\right) \mathrm{As} \to \mathrm{H} = \mathrm{\Delta EN} = 0.02 \\ \left(\mathrm{f}\right) \mathrm{S} \to \mathrm{N} = \mathrm{\Delta EN} = 0.46 \end{gathered}$$

Thus, H-O has more polar bond.