Chapter 18.SE, Problem 62GP

The Zeisel method is an old analytical procedure for determining the number of methoxyl groups in a compound. A weighed amount of the compound is heated with concentrated HI, ether cleavage occurs, and the iodomethane product is distilled off and passed into an alcohol solution of AgNO₃, where it reacts to form a precipitate of silver iodide. The Agl is then collected and weighed, and the percentage of methoxyl groups in the sample is thereby determined. For example, 1.06 g of vanillin, the material responsible for the characteristic odor of vanilla, yields 1.60 g of Agl. If vanillin has a molecular weight of 152, how many methoxyl groups does it contain?