Refer to graph of a chemical reaction. what is true of the reaction shown here?

a* the reaction rate speeds up over time.

b* the rate of the reaction is not constant.

c* the reaction rate is consistently slow.

d* the rate of the reaction does not change with time.

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.