6. Which of the following statements is/are TRUE of metals and non-metals? l. Non-metals are heat conductors.
ll. Aluminum, copper and iron are non-metals.
III. Phosphorus and sulfur are poor conductors of heat and electricity
IV. Metals have luster.

A. I only
B. III only
C. III and IV
D. I and II

I= true

III=false

iv=true

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.

the answers are

c and c