Question -
Answer -
Both acidic (carboxyl) as well as basic (amino) groups arepresent in the same molecule of amino acids. In aqueous solutions, the carboxylgroup can lose a proton and the amino group can accept a proton, thus givingrise to a dipolar ion known as a zwitter ion.
Due to this dipolar behaviour, they have strongelectrostatic interactions within them and with water. But halo-acids do notexhibit such dipolar behaviour.
For this reason, the melting points and the solubility ofamino acids in water is higher than those of the corresponding halo-acids.