Chemistry and Chemical Reactivity (9th Edition)

$11.5\%$
Number of moles of AgCl: $0.1840\ g\div 143.33\ g/mol=1.284\ mmol$ From stoichiometry, number of moles of the compound: $0.642\ mmol$ Mass of the compound: $0.642\ mmol\times 221.03\ mg/mmol=141.9\ mg$ Mass percentage: $0.142/1.236\times 100\%=11.5\%$