a) Cu(OH)₂, KOH, Fe(OH)₃, NaOH, Al(OH)₃, Mg(OH)₂, Ba(OH)₂, Zn(OH)₂

Cu(OH)₂ + 2HCl → CuCl₂ + 2H₂O

KOH + HCl → KCl + H₂O

Fe(OH)₃ + 3HCl → FeCl₃ + 3H₂O

NaOH + HCl → NaCl + H₂O

Al(OH)₃ + 3HCl → AlCl₃ + 3H₂O

Mg(OH)₂ + 2HCl → MgCl₂ + 2H₂O

Ba(OH)₂ + 2HCl → BaCl₂ + 2H₂O

Zn(OH)₂ + 2HCl → ZnCl₂ + 2H₂O

b) Cu(OH)₂, Fe(OH)₃, Al(OH)₃, Mg(OH)₂, Zn(OH)₂

c) KOH, NaOH, Ba(OH)₂

\[3KOH + FeC{l_3} \to 3KCl + Fe{(OH)_3} \downarrow \]

\[3NaOH + FeC{l_3} \to 3NaCl + Fe{(OH)_3} \downarrow \]

\[3Ba{(OH)_2} + 2FeC{l_3} \to 3BaC{l_2} + 2Fe{(OH)_3} \downarrow \]

d) KOH, NaOH, Ba(OH)₂

e) KOH, NaOH, Ba(OH)₂

\[2KOH + C{O_2} \to {K_2}C{O_3} + {H_2}O\]

\[2NaOH + C{O_2} \to N{a_2}C{O_3} + {H_2}O\]

\[Ba{(OH)_2} + C{O_2} \to BaC{O_3} \downarrow + {H_2}O\]

\[KOH + C{O_2} \to KHC{O_3}\]

\[NaOH + C{O_2} \to NaHC{O_3}\]

\[Ba{(OH)_2} + 2C{O_2} \to Ba{(HC{O_3})_2}\]