C2H5OH+H2SO4=C2H4+H2SO4+H2O
n C2H5OH=100/46=2.17 моль
n C2H4=2.17*0.85=1.85 моль
V C2H4=1.85*22.4=41.4 л
AlCl3+NaOH =AlOHCl2+NaCl
AlCl3+ 2NaOH= Al(OH)2Cl+2NaCl
AlCl3+4NaOH= Na[Al(OH)4] +3NaCl
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2Hg + O2 = 2HgO
Cумма коэффициентов = 2+1+2 = 5
Ответ: 5