Question

1. PABA is _______.

2. The molecule contains both a C O O H ______ group and an − N H 2 ______ group. It can act like an H +blank.

Answer 1

Step-by-step explanation:

According to Bronsted-Lowry, an acid is defined as the specie which is able to donate hydrogen ions when dissolved in water.

For example,
`HCl \rightarrow H^(+) + Cl^(-)`

On the other hand, bases are the species which are able to donate hydroxide ions when dissolved in water.

For example,
`NaOH \rightarrow Na^(+) + OH^(-)`

It is known that the full form of PABA is para-aminobenzoic acid. It's chemical formula is
`C_(7)H_(7)NO_(2)`. This compound can take up a proton and also it is able to lose a proton.

Therefore, PABA acts as both an acid and a base.

The carboxylic group has a chemical formula COOH and it can easily donate a hydrogen ion. Therefore, it is an acid.

And,
`NH_(2)` contains a lone pair of electrons and it is difficult for it to lose a hydrogen ion but it can readily gain a hydrogen ion. Therefore, this group acts as a base.

Thus, we can conclude that PABA is both an acid and a base. The molecule contains both a C O O H; carboxylic group and an − N H 2; amine group. It can act like an
`H^(+)` donor or acceptor.