Răspuns:
-calculez masa de acid dizolvat in solutia data
c=mdx100/ms---> md=cxms/100=40x500/100g= 200gH2S04
M,H2SO4=98g/mol
M,Na2CO3=106g/mol
-calculez masa de carbonat consumat, din ecuatia chimica
1mol................1mol
Na2CO3+H2SO4----> Na2SO4 + H2O+CO2
106g................98g
x........................200g
x=m=216,3 g Na2CO3
Explicație: