Răspuns:
cel mai electronegativ nemetal din gr.ViA este O2
metalul are configuratia electronica K2 L8 M1--> Z=11-> Na
4Na + O2---> 2Na2O
1mol............2mol
5mol.............x= niu= 10molNa2O
Na2O + H2O----> 2NaOH
1mol........1mol...............2mol
10mol........y....................x= niu=20molNaOH
y=10mol H2O
M,NaOH= 40g/mol M,H2O= 18g/mol
mNaOH=niuxM= 20molx40g/mol= 800g
m,H2O= niuxM= 10molx18g/mol= 180g-
solutia este formata din masa de NaOH dizolvata in masa de apa ramasa
c=mdx100/ms
md= 800gNaOH
m,apa= 600-180-> 420g
ms= md+m,apa= 1220g
c= 800x100/1220=>65,6%
Explicație: