Răspuns:
Explicație:
40g NaOH
c=10%
r. cu FeCl3
g,moli FeCl3
-se afla md sol. de NaOH
md= 10. 40 : 100=4g NaOH
4g xg
3NaOH + FeCl3= Fe(OH)3 +3 NaCl
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
MF e(OH)3 =56 +3.16 +3=107------>107g/moli
MNaOH =23 +16 +1=40-------> 40g/moli