This is a precipitation reaction: Al(OH)3 is the formed precipitate.
Reactants:
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Al2(SO4)3 – Aluminium sulfate
Other names: Aluminum sulfate, Aluminium sulphate, Cake alum
Appearance: White crystalline solid | hygroscopic ; Odourless white hygroscopic lustrous crystals or powder
NaOH
Names: Sodium hydroxide, Caustic soda, Lye
Appearance: White, waxy, opaque crystals ; White hygroscopic solid in various forms ; Colorless to white, odorless solid (flakes, beads, granular form).