Estimate the environmental value of fuel, C5H12. The environmental value is the amount of energy obtained per mole of carbon dioxide
produced. The heat of combustion for pentane is -3535 kJ/mol.
CH22 80
5002 +6H20
kJ/mol

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.