HF or Hydroflouric Acid
Hydrofluoric acid is a solution of hydrogen and fluoride mixed with water. Its chemical formula is HF. It is a chemical compound and considered a weak acid but can be heavily corrosive.
A commercial name is crystal.
The chemical name for Nia cleaning solution is Sodium Hypochlorite.
The chemical name for NH4OH is ammonium hydroxide. This is also referred to as ammonia solution and is a solution comprised of ammonia in water.
A Base
If the etching is one of a kind, I recomend looking for the name of the artist on the etching. If there is a name, you can look up the artist and get a general idea of what a piece of his/her art is worth. If there are more than one sculpture/etching of this same theme. Try to find the price or value of the other.
Name the unit of 2.
The formula is for potassium chloride in water solution.
Sulfuric Acid (or sulphuric if you're in the UK!)
Nitrogen trifluoride
Another name for a solution in chemistry is a homogeneous mixture. In the context of chemical reactions, a solution is defined as a mixture where one or more substances (solute) are dissolved in another substance (solvent) to form a uniform mixture.
CH3COOH(aq) has more than one chemical name. It is acetic acid, also known as ethanoic acid. The (aq) simply means an aqueous solution.