Răspuns:
Explicație:
ms1=400g sol. HCl
c1=30%
ms2=200g sol. HCl
c2=50%
mapa=200g
c3=?
md1= ms1 . c1 : 100
md1= 400 . 30 : 100=120g HCl
md2= ms2 . c2 : 100
md2=200 . 50 : 100 = 100g HCl
ms3= ms1 + ms2 + mapa
ms3= 400 + 200 + 200=800g sol. HCl
md3= md1 + md2
md3=120 + 100= 220g HCl
c3= md3 .100 : ms3
c3= 220 . 100 : 800=27,5%