The molecular formula of butane is C4H10C4H10. It is obtained from petroleum and is used commonly in LPG (Liquefied Petroleum Gas) cylinders (a common source of cooking gas). It has two arrangements of carbon atoms: a straight chain and a branched chain. Required:
a. Using this information, draw the structure of the tertiary butyl radical that will form upon removal of a hydrogen atom.
b. Draw the molecule on the canvas by choosing buttons from the Tools (for bonds), Atoms, and Advanced Template toolbars.

Explanation:

Butane is an alkane with the molecular formula C₄H₁₀.

(a) It has two structural isomers (n-butane and 2-methylpropane) shown below

     H   H   H   H

      |     |     |     |

H - C - C - C - C - H

      |     |     |     |

     H   H   H   H

The structure above is n-butane

     H     CH₃ H

      |       |       |

H - C  -  C  -  C - H

     |       |       |

    H     H     H

The structure above is 2-methylpropane and can also be referred to be a tertiary butane because the central carbon atom has 3 methyl groups attached to it as shown below.

        CH₃

         |

H₃C - C - CH₃

         |

        H

Hence, the structure of a tertiary butyl radical after loss/removal of a hydrogen atom will be

         CH₃

          |

H₃C - C⁻ - CH₃

NOTE: It should be noted that the central carbon becomes negatively charged after the loss of the hydrogen atom

(b) This is the practical part of the structure drawn above. The last structure illustrated above can be drawn on the canvas with the instruction provided in the question.

substituting a hydrogen atom with a halogen in a hydrocarbon:

- the single bond remains single. a is wrong.

- the bond with hydrogen is as strong as with a halogen. c is wrong

- a hydrocarbon is saturated if there is no double bond. we do not know that so d is wrong.

- carbon will always have four valence electrons. e is wrong.

by elimination, the correct answer is b. the boiling point of the new compound increases.