91Ó°ÊÓ

The molecules containing atoms or ions of high molecular masses are placed at the first priority. The order of the priority of some groups is:

$\text{H<C<O<F<Cl<Br<I}$

The double bonded groups are multiplied by the same group on the place of a bond.

a. The order of priority is shown as:

${\text{-OH>-NH}}_2\text{>-COOH>-H}$

The order of the highest priority follows as:

$\text{H<C<N<O}$

Therefore, -OH has the highest priority and H has the lowest priority.

b. The order of priority is shown as:

${\text{-CH(CH}}_3{\text{)}}_2{\text{>-CH}}_2{\text{CH}}_3{\text{>-CH}}_3\text{>-H}$

The order of the highest priority follows as:

$\text{H<C}$

Therefore, ${\text{-CH(CH}}_3{\text{)}}_2$has the highest priority (highest molecular mass) and H has the lowest priority.

c. The order of priority is shown as:

${\text{-Cl>-CH}}_2{\text{Cl>-CH}}_3\text{>-H}$

The order of the highest priority follows as:

$\text{H<C<Cl}$

Therefore, Cl has the highest priority (highest molecular mass), and H has the lowest priority.

d. The order of priority is shown as:

${\text{-°ä≡C±á\&²µ³Ù;-°ä±á=°ä±á}}_2{\text{>-CH}}_3\text{>-H}$

The order of the highest priority follows as:

$\text{±á\&±ô³Ù;°ä\&±ô³Ù;°ä=°ä\&±ô³Ù;°ä≡C}$

Therefore, $\text{°ä≡C±á}$has the highest priority (the triple bond triples each carbon in the molecule) and H has the lowest priority.