2Fe(OH)3\(\rightarrow\)Fe2O3+3H2O
\(m_{H_2O}=0,81gam\)
\(n_{H_2O}=\dfrac{0,81}{18}=0,045mol\)
\(n_{Fe\left(OH\right)_3\left(PU\right)}=\dfrac{2}{3}n_{H_2O}=\dfrac{2}{3}.0,045=0,03mol\)
\(n_{Fe_2O_3}=0,045:3=0,015mol\)
\(n_{HCl}=0,06.2=0,12mol\)
Fe2O3+6HCl\(\rightarrow\)2FeCl3+3H2O
Fe(OH)3+3HCl\(\rightarrow\)FeCl3+3H2O
\(n_{Fe\left(OH\right)_3\left(dư\right)}=\dfrac{1}{3}\left(0,12-0,015.6\right)=0,01mol\)
\(n_{Fe\left(OH\right)_3\left(bđ\right)}=0,03+0,01=0,06mol\)
H=\(\dfrac{0,03}{0,06}.100=50\%\)