2NaOH+H2SO4----------->Na2SO4+2H2O
md=ms*c/100
mdH2SO4=980*10/100=98 g
din ec. reactiei :
2*40 g NaOH.........98 g H2SO4..........142
g Na2SO4
===>
==> mNaOH=80 g (md) atunci ms=md*100/c=80*100/10=800 g sol. NaOH
mNa2SO4=142 g ==>
n=m/M=142g/142g/mol= 1 mol
Na2SO4