Răspuns :

ms1 = 80g, c1= 5,6%

ms2 = ?g, c2%= 7,3%

ms3 = ?g,

stim ca c% = mdx100/ms

=> md1 = ms1xc1/100 = 80x5,6/100 = 4,48g KOH

dupa reactie se obtine KCl care este md.final si apa nou formata la care se va adauga si apa din cele doua solutii ms1 si ms2

4,48g    md2    md3   m

KOH  + HCl --> KCl + H2O

56         36,5     74,5   18

=> md2 = 4,48x36,5/56 = 2,292g HCl consumat

=> ms2 = md2x100/c2 = 2,292x100/7,3 = 40g sol. HCl

=> md3 = 4,48x74,5/56 = 5,96g KCl format

=> m = 4,48x18/56 = 1,44 g apa nou formata

din S1=> m.apa1= 80-4,48 = 75,52g

din S2=> m.apa2 = 40-2,292 = 37,708g

=> m.apa.final = m.apa1 + m.apa2 + m = 1,44+75,52+37,708 = 114,67 g

=> ms.final = md3 + m.apa.final = 5,96 + 114,67 = 120,63 g

=> c%.final = md3x100/ms.final = 5,96x100/120,63 = 4,94%