Which of the following is the best way to prepare 250.mL of a solution that contains 0.100MKCl (molar mass 74.55gmol1 )? Dissolve 1.86gKCl in a 250.mL volumetric flask and then fill the flask to the 250. mLmark. Fill a 250mL beaker with water, then add 29.8gKCl. Dissolve 29.8gKCl in a 250. mL volumetric flask and then fill the flask to the 250.mL mark. Fill a 250. mL volumetric flask with water, then add 1.86gKCl