$1.$ The process of separating crude oil into its various components is known as:

a$)$ Combustion

b$)$ Distillation

c$)$ Polymerization

d$)$ Oxidation

$2.$ Which of the following is a characteristic property of gasoline?

a$)$ High flash point

b$)$ Low vapor pressure

c$)$ Low octane rating

d$)$ High sulfur content

$3.$ The refining process that converts low$-$value, high$-$boiling fractions of crude oil into high$-$value, low$-$boiling ones is called:

a$)$ Reforming

b$)$ Cracking

c$)$ Alkylation

d$)$ Isomerization

$4.$ Which refining process involves the addition of hydrogen to remove impurities?

a$)$ Cracking

b$)$ Reforming

c$)$ Hydrocracking

d$)$ Polymerization