Question

exercise 10.85 - enahnced - with feedback
arrange the following diatomic molecules in order of decreasing bond polarity.
rank the compounds from most to least polar. to rank items as equivalent, overlap them.
hbr icl h₂ co
most polar least polar

Explanation:

Bond polarity depends on the electronegativity difference ($\Delta \text{EN}$) between the two atoms in the bond. The greater the $\Delta \text{EN}$, the more polar the bond.

• For $\text{HBr}$: $\text{EN}$ of $\text{Br} = 2.96$, $\text{EN}$ of $\text{H}=2.20$. $\Delta \text{EN}=2.96 - 2.20= 0.76$.
• For $\text{ICl}$: $\text{EN}$ of $\text{Cl}=3.16$, $\text{EN}$ of $\text{I}=2.66$. $\Delta \text{EN}=3.16 - 2.66 = 0.50$.
• For $\text{H}_2$: Both atoms are $\text{H}$, so $\Delta \text{EN}=2.20 - 2.20=0$.
• For $\text{CO}$: $\text{EN}$ of $\text{O}=3.44$, $\text{EN}$ of $\text{C}=2.55$. $\Delta \text{EN}=3.44 - 2.55 = 0.89$.

Answer:

$\text{CO}$, $\text{HBr}$, $\text{ICl}$, $\text{H}_2$