12. ORGANIC CHEMISTRY SOME BASIC PRINCIPLES AND TECHNIQUES (HM)
Explanation:
(a) \(\mathop {\mathop {COOH}\limits^{1\,\,\,\,\,\,\,\,\,\,\,\,\,\,} - \mathop {C{H_2}}\limits^{2\,\,\,\,\,\,\,\,\,} - \mathop {C{H_2}}\limits^{3\,\,\,\,\,\,\,\,\,\,} - \mathop {COOH}\limits^{4\,\,\,\,\,\,\,\,\,\,\,\,\,\,} }\limits_{{\rm{1,4}} - {\rm{butandioic}}\,{\rm{acid}}} \)