Юлия ZnCl2 + 2NaOH = 2NaCl + Zn(OH)2 Zn(OH)2 = ZnO + H2O m ZnO = 0.2г v ZnO = 0.2/81 = 0.0025 моль v Zn(OH)2 = 0.0025 моль v NaOH = 2*0.0025 = 0.005 моль m NaOH = 40*0.005 = 0.2г w NaOH = 0.2*100/50 = 0.4%