a,\(n_{SO_3}=\dfrac{2,8}{22,4}=0,125\left(mol\right)\)
PTHH: 2NaOH + SO3 → Na2SO4 + H2O
Mol: 0,25 0,125 0,125
\(\Rightarrow m_{Na_2SO_4}=0,125.142=17,75\left(g\right)\)
b,mNaOH = 0,25.40 = 10 (g)
\(C\%_{ddNaOH}=\dfrac{10.100\%}{480}=2,08\%\)
c,mdd sau pứ = 480 + 0,125.80 = 490 (g)
\(C\%_{ddNa_2SO_4}=\dfrac{17,75.100\%}{490}=3,62\%\)