Hi, I got this question for my chemistry class, and I simply don't know where to start. Do I have to find out the volume of HCl first? The label on a bottle of hydrochloric acid says the solution is 3.7% hydrogen chloride. You wish to the determine the actual concentration. You fill a burette with the acid, but before you do the titration, you would like to know how much acid you need to add to the 10 mL of 1.0 mol/L sodium hydroxide to turn the blue bromthymol blue solution green. You can assume the density of the dilute acid is essentially that of water.