chemistry 1a study assignment 9: solution reactions, dilutions, and principal substances in solution examples using net ionic equations and solution stoichiometry, calculate the molarity of the principal substances (ions and/or molecules) in solution, or the number of millimoles of insoluble species (solids or gases) present after the following are mixed: 1. 200. ml of 0.100 m naoh and 150. ml of 0.200 m hcl.