\(n_{Zn\left(NO_3\right)_2}=\dfrac{18,9}{189}=0,1mol\)
\(n_{NaOH}=0,2.1,5=0,3mol\)
Zn(NO3)2+2NaOH\(\rightarrow\)Zn(OH)2\(\downarrow\)+2NaNO3
\(n_{NaOH\left(pu\right)}=n_{NaNO_3}=2n_{Zn\left(NO_3\right)_2}=0,2mol\)
nNaOH(dư)=0,3-0,2=0,1mol
\(n_{Zn\left(OH\right)_2}=n_{Zn\left(NO_3\right)_2}=0,1mol\)
2NaOH+Zn(OH)2\(\rightarrow\)Na2ZnO2+2H2O
\(n_{Zn\left(OH\right)_2\left(pu\right)}=n_{Na_2ZnO_2}=\dfrac{1}{2}n_{NaOH}=0,05mol\)
\(n_{Zn\left(OH\right)_2\left(dư\right)}=0,1-0,05=0,05mol\)
Trong 200ml dung dịch có: NaNO3 0,2 mol và Na2ZnO2 0,05 mol
[Na+]=\(\dfrac{0,2+0,05.2}{0,2}=1,5M\)
[NO3-]=\(\dfrac{0,2}{0,2}=1M\); [ZnO22-]=\(\dfrac{0,05}{0,2}=0,25M\)
