Question

A zwitterion is kept in a uniform electric field. Select the correct statement with regard to the movement of the zwitterion.

• A. It moves towards the anode
• B. It moves towards the cathode
• C. It moves along the direction of the electric field
• D. It neither moves towards anode nor towards the cathode

Answer 1

The correct option is D It neither moves towards anode nor towards the cathode

When an amino acid is dissolved in water at a particular pH, it exists in solution as dipolar ion or zwitterion. The ionisable nature of $N{H}_2$ and COOH groups can cause them to form $N{H}_3^{+}$ and $CO{O}^{-}$ by gain and loss of a proton respectively at a particular range of pH. At this point, the net charge on an amino acid becomes zero. Since the net charge on zwitterion is zero, it will neither move towards anode nor towards the cathode.