25-7. If a 15-cm-long HPLC column has a plate height of 5.0 mm, what will be the half-width (in seconds) of a peak eluted at 10.0 min? If plate height 5 25 mm, what will be w1/2?

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.