Animated Solution for Chemistry - Organic Chemistry: A substance forms Zwitter ion. It can have functional groups

Have you ever wondered how a single molecule can act like a tiny magnet, possessing both a positive and a negative pole, yet remaining completely neutral overall? Welcome to the fascinating world of Zwitterions!

The term "Zwitterion" comes from the German word Zwitter, meaning "hermaphrodite" or "hybrid." In chemistry, it refers to a molecule that contains both positive and negative electrical charges, but its net charge is exactly zero.

For a molecule to achieve this unique state, it needs to have a split personality. It must contain: 1. An acidic group that is willing to donate a proton ($H^{+}$). 2. A basic group that is eager to accept that proton.

When these two groups are present in the same molecule, an internal acid-base reaction occurs. The acidic group tosses its proton over to the basic group. The result? The acidic part becomes negatively charged, and the basic part becomes positively charged.

Let's look at the functional groups provided in the question.

Option (a): $-{\text{NH}}_2$ and $-\text{COOH}$ Here, we have an amine group ($-{\text{NH}}_2$) which is basic, and a carboxylic acid group ($-\text{COOH}$) which is acidic. This is the classic setup found in all amino acids. The $-\text{COOH}$ group donates a proton to the $-{\text{NH}}_2$ group, forming $-{\text{COO}}^{-}$ and $-{\text{NH}}_3^{+}$. This perfectly forms a Zwitterion!

Option (b): $-{\text{NH}}_2$ and $-{\text{SO}}_3\text{H}$ In this case, we have the same basic amine group ($-{\text{NH}}_2$), but the acidic group is now a sulfonic acid group ($-{\text{SO}}_3\text{H}$). Sulfonic acid is actually a stronger acid than carboxylic acid. It will readily donate its proton to the amine group, forming $-{\text{SO}}_3^{-}$ and $-{\text{NH}}_3^{+}$. A classic example of this is sulphanilic acid, which exists almost entirely as a Zwitterion.

Since both combinations of functional groups contain a basic proton acceptor and an acidic proton donor, both are fully capable of undergoing an internal proton transfer to form a Zwitterion.

Therefore, the correct answer is Both (a) and (b).

Understanding Zwitterions is crucial because they are the fundamental building blocks of proteins in our bodies. Every time you flex a muscle or digest a meal, you have these tiny, dual-charged molecules to thank!