Answer:
a. 
Turn paper Blue - these are alkaline/ base substances. 
Turn paper Red - these substances are acidic in nature.
- Lemon Juice
 - Vinegar
 - Cola drink
 
b. i. A wasp sting - Lemon juice
ii. A bee sting - Toothpaste
iii. A wasp sting is alkaline which means that running an acidic substance like lemon or lemon juice on it should neutralize it. 
A bee sting is acidic so an alkaline substance such as toothpaste should neutralize it as well.