Its arbitrary. It was developed on the greek phoenetic system and never reallybwas explained.
Answer:
<u><em>Benzaldehyde </em></u>(C6H5CHO) is an organic compound consisting of a benzene ring with a formyl substituent. It is the simplest aromatic aldehyde and one of the most industrially useful.
Sometimes negative sometimes positive, your answer is B!
What class is this for because it depends
I will take a stab at it, but there are not equations, did you forget them?