This is part of a lab so it is not a set problem. You need to add an excess of Ag(aq) to a solution of Cl but you do not know how much CL is in the solution. The chloride content is 65% and you use this to calculate the amount of Ag(aq) to use for precipitation, you will have calculated an excess of Ag(aq). You will be using 0.2 M AgNO3 to furnish the Ag(aq) therefore calculate the number of mL of 0.2 M AgNO3(aq) needed for the precipitation.