a.
Bảo toàn điện tích :
\(n_{NO_3^-}=0.01\cdot3+0.02-0.02\cdot2=0.01\left(mol\right)\)
b.
\(n_{Ba\left(OH\right)_2}=0.1\cdot0.3=0.03\left(mol\right)\)
\(Ba^{2+}+SO_4^{2-}\rightarrow BaSO_4\)
\(0.02.....0.02..........0.02\)
\(Ba^{2+}dư\)
\(m_{BaSO_4}=0.02\cdot233=4.66\left(g\right)\)
\(NH_4^++OH^-\rightarrow NH_3+H_2O\)
\(0.02.......0.02........0.02\)
\(V_{NH_3}=0.02\cdot22.4=0.448\left(l\right)\)
\(OH^-dư\)