What is HC6H5O?

Answer 1

Several organic compounds have that formula.

However, the way that it's written... with a lone hydrogen in front... strongly implies that the answer is probably phenol.

Phenol is a benzene ring with an alcohol group attached to one of the carbons. The hydrogen in the alcohol is less strongly held than is typical of alcoholic hydrogens, so phenol is a weak acid (most alcohols are neutral) and even has the older name of "carbolic acid" to reflect this.

Answer 2

It is

more properly formulated as KC4H5O6

it is used as a pesticide

http://www.pesticideinfo.org/Detail_Chemical.jsp?Rec_Id=PC36442

Answer 3

It's potassium sodium tartrate, also known as Seignette's salt or Rochelle salt.

Answer 4

KHC8H4O4 is the molecular formula for potassium hydrogen phthalate. The structure of this molecule is tetrahedral. It is often used as a primary standard for acid-base titrations.

Answer 5

KC2H3O2 is potassium acetate.

Answer 6

Potassium Hydrogen Tartrate

Answer 7

Potassium hydrogen phthalate