The solubility in water of amino acids are generally higher than that of the corresponding halo acids. Explain.

Explanation

The high melting points and solubility in water of amino acids is due to the presence fo both acidic carboxylic (-COOH) group and basic amine `(-NH_2)` group in the same molecule.
`H_2 N underset(alpha-"Amino acid")underset(R)underset(|)overset(COOH)overset(|)C-H`
In aqueous solution, the -COOH group can lose a proton and `-NH_2` group can accept a proton, giving rise to a dipolar ions known as zwitter ion. This is neutral but contains both +ve and -ve charge. Due to this salt like character, amino acids interact strongly with water and are highly soluble in water.
`R-underset(NH_2)underset(|)CH-overset(O)overset(||)C-O-H hArr R- underset(""^+NH_3)underset(|)CH-overset(O)overset(||)C-O^-`
Such behaviour is not possible in case of halo-acids. As such halo-acids have lower melting points and lower solubility in water than amino acids.