Răspuns:
Explicație:
ms NaOH=50g
c=8%
FeCl3
masa de precipitat
-se afla md sol. de NaOH
md= c . ms : 100
md= 8 .50 : 100=4g NaOH
4g xg
3 NaOH + FeCl3= 3NaCl + Fe(OH)3
3. 40g 107g
x=4 . 107 : 120=3,56 g Fe(OH)3
n= m:M
n=3,56g : 107g/moli=0,033 moli precipitat
MNaOH=23 +16 +1=40------>40g/moli
MFe(OH)3= 56+3.16 +3=107------->107g/moli