Răspuns:
Explicație:
200g sol. NaOH
c=15%
g,moli Fe(OH)3
g,moli FeCl3
-se afla md sol. de NaOH
md=c.ms :100
md=15.200 :100=30 g NaOH
xg 30g yg
FeCl3 + 3NaOH = Fe(OH)3 ↓ + 3NaCl
162,5g 3 .40g 107g
x=162,5 . 30 : 3 . 40=40,625 g FeCl3
n=40,625g : 162,5g/moli=0,25 moli FeCl3
y=30 . 107 : 3 . 40 =26,75 g precipitat
n=26,75g : 107g/moli=0,25 moli Fe(OH)3
MFeCl3=56 +3.35,5=162,5------->162,5 g/moli
MFe(OH)3=56+ 3.16 +3=107------->107g/moli