using the balanced equation 2NACL(s) + H2SO4(aq) ---> 2HCl(aq) + Na2SO4(aq). A.) If 20. g of NaCl are used, how many grams of H2SO4 are required for complete reaction? B.) if 20. g or NaCl are used and only 5.6 g of HCl are isolated, what is the percent yield of HCl? C.) If only 5.6 g of HCl are obtained, how many grams of Na2SO4 must also have been formed?