Which of the following is an example of +δs
a) a solid being sublimed
b)a gas being condensed to form a liquid
c)a liquid freezing to a solid
d)a gas being compressed at a low temperature to a solid

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 answer is 0.42 is that is an option. this question provides no info