Răspuns:
c1=40%
ms2=1000g
c2=10%
c=mdx100/ms---> md2= c2xms2/100= 10x1000/100g= 100g acid
aceasta masa de acid trebuie sa se gaseasca si in solutia initiala,deci
md1=md2
atunci, ms1= md1x100/c1= 100x100/40g=250g
masa de apa adaugata = ms2-ms1=1000-250=>750g
Explicație: