question_answer

18 C-H and 7 C-C sigma bonds are present in:

A)  cyclo hexane

B)  3, 3-dimethyl pentane

C)  2, 2, 3-trimethyl pentane

D)  \[n-\] heptane

Correct Answer: C

Solution :

                 Structure of cyclohexane is It contains \[\text{6}\,\,\text{C}-\text{C}\]bond and \[12\,\text{C}-\text{H}\] bonds. Structure of \[3,3-\]dimehyl pentane, \[H-\underset{H}{\overset{H}{\mathop{\underset{|}{\overset{|}{\mathop{C}}}\,}}}\,-\underset{H}{\overset{H}{\mathop{\underset{|}{\overset{|}{\mathop{C}}}\,}}}\,-\underset{C{{H}_{3}}}{\overset{C{{H}_{3}}}{\mathop{\underset{|}{\overset{|}{\mathop{C}}}\,}}}\,-\underset{H}{\overset{H}{\mathop{\underset{|}{\overset{|}{\mathop{C}}}\,}}}\,-\underset{H}{\overset{H}{\mathop{\underset{|}{\overset{|}{\mathop{C}}}\,}}}\,-\underset{H}{\overset{H}{\mathop{\underset{|}{\overset{|}{\mathop{H}}}\,}}}\,-H\] It contains \[\text{6}\,\,\text{C}-\text{C}\]bond and \[\text{16}\,\,C-H\] bonds. Structure of 2,\[3,3-\]trimethyl pentane. It contains \[7C-C\]bond and \[18\,C-H\]bonds. So, it is the answer. Structure of \[n-\]heptane \[H-\underset{H}{\overset{H}{\mathop{\underset{|}{\overset{|}{\mathop{C}}}\,}}}\,-\underset{H}{\overset{H}{\mathop{\underset{|}{\overset{|}{\mathop{C}}}\,}}}\,-\underset{H}{\overset{H}{\mathop{\underset{|}{\overset{|}{\mathop{C}}}\,}}}\,-\underset{H}{\overset{H}{\mathop{\underset{|}{\overset{|}{\mathop{C}}}\,}}}\,-\underset{H}{\overset{H}{\mathop{\underset{|}{\overset{|}{\mathop{C}}}\,}}}\,-\underset{H}{\overset{H}{\mathop{\underset{|}{\overset{|}{\mathop{H}}}\,}}}\,-H\] It contains \[6\,\,C-C\]bonds and element having atomic number 24 is: