When concentration is expressed in percentage, it is a ratio of parts solute to parts solution. For mass percentage, that would be the amount of grams solute per 100 grams of solution. Thus,
7.62% = Mass solute/Mass solution * 100
7.62% = Mass solute/190 g * 100
Mass solute = 14.478 g of KOH
That means that the amount of water would be
Mass of water = 190 g - 14.478 g = 175.522 g
Since the density of water is 1 g/mL, the volume of water is:
Volume = 175.522 g * 1 mL/g = 175.522 mL water
