What was daltons motivation for proposing his model of the atom

John Dalton based his partial pressures theory on the idea that only like atoms repel one another, Whereas unlike atoms appear to react indifferently. This notion was erroneous, but it helped to explain why each gas in a mixture behaved independently, serving the purpose of showing that atoms of all kinds are not alike.

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.