**HCl, also known as hydrochloric acid, maintains a density of 1.49 grams per cubic centimeter when measured at standard temperature and pressure values of 68 degrees Fahrenheit and 1 standard atmosphere unit.** The density also depends on the molarity of the solution, related to its concentration.

As the concentration of the hydrochloric acid increases, so does its density. For example, while a 10 percent solution has a density of 1.048 grams per cubic centimeter, a hydrochloric acid solution at 38 percent concentration has the higher density of 1.189 grams per cubic centimeter. The density also varies based on the solution's temperature and pressure.