Look for heating and cooling processes at home. observe them carefully that how heat is being transferred in these processes. give five examples??

a polar bond is formed when electrons are shared unevenly between atoms

it is the most commonly accepted one

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.