Answer: Chemicals become positively charged by loosing electrons.
Explanation: There are three types of compounds:
1) Neutral compounds: These are the compounds where equal number of protons and electrons are present.
2) Positive compounds: These are the compounds where number of protons are more than the electrons. These are considered as cations.
3) Negative compounds: These are the compounds where number of electrons are more than the protons. These are considered as anions.
So, in order to have a positive charge on a compound, that compound has to loose electrons, so that the number of protons gets higher than the number of electrons.