Răspuns:
Explicație:
1.
100 g solutie........................80 g NaCl....................20 g apa
x...........................................68 g NaCl....................y
x = 68*100/80 = 85 g solutie
y = 68*20/80 = 17 g apa
2.
400*30/100 = 120 g HCl in solutia 30%
100*15/100 = 15 g HCl in solutia 15%
400 + 50 + 100 = 550 g solutie finala
120 + 50 + 15 = 185 g HCl in solutia finala
c% = (185/550)*100 = 33,6%