33) 1 When smoke particles are observed with a microscope they are seen to move around randomly. This is called Brownian motion.
What causes Brownian motion?
A diffusion of the smoke particles
B molecules in the air hitting the smoke particles
C sublimation of the smoke particles
D the smoke particles hitting the walls of the container

im pretty sure its b

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.

c. orbital shape i hope this is correct