Answer

Sometimes the acid is, or can become, a yellowish colour. This is due to the presence of re-dissolved chlorine (hydrogen chloride) and this can occur as a result of contact with air or when bottling down from bulk. By definition it should be water clear to yellowish. Our MSDS states this acid is light yellow in colour. Even when yellow, the acid is quite normal and is perfectly alright to use. Also, on diluting down, the solution will turn clear. The molarity is approximately 11.65 M.