• # question_answer The most stable carbonium ion is A) ${{C}_{6}}{{H}_{5}}\overset{+}{\mathop{C}}\,{{H}_{2}}$             B) ${{(C{{H}_{3}})}_{3}}\overset{+}{\mathop{C}}\,$C) $C{{H}_{3}}-\underset{+}{\mathop{C}}\,{{H}_{2}}$             D) ${{({{C}_{6}}{{H}_{5}})}_{3}}\overset{+}{\mathop{C}}\,$

${{({{C}_{6}}{{H}_{5}})}_{3}}{{C}^{+}}$is the most stable. As the three ${{C}_{6}}{{H}_{5}}^{-}$groups attached to the carbonium ion stabilizes it due to resonance. Here the order of stability is given as follows: ${{({{C}_{6}}{{H}_{5}})}_{3}}\overset{+}{\mathop{C}}\,>{{(C{{H}_{3}})}_{3}}\overset{+}{\mathop{C}}\,>{{C}_{6}}{{H}_{5}}\overset{+}{\mathop{C}}\,{{H}_{2}}>{{\overset{+}{\mathop{C}}\,}_{2}}>{{\overset{+}{\mathop{C}}\,}_{2}}{{H}_{5}}$ Hence, the correct option is [d].