This is an acid-base reaction (neutralization): Zn(OH)2 is a base, HCl is an acid.
Reactants:
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Zn(OH)2
Names: Zinc hydroxide, Zinc(II) hydroxide
Appearance: White powder
HCl – Chlorane, Hydrogen chloride
Other names: Hydrochloric acid, M, Uriatic acid
Appearance: Colorless, transparent liquid, fumes in air if concentrated ; Colorless gas ; Colourless compressed liquefied gas with pungent odour ; Colorless to slightly yellow gas with a pungent, irritating odor. [Note: Shipped as a liquefied compressed gas.]
Products:
ZnCl2 – Zinc chloride
Other names: Zinc(II) chloride, Zinc dichloride, Butter of zinc
Appearance: White crystalline solid | hygroscopic and very deliquescent ; White hygroscopic odourless solid in various forms ; White particulate dispersed in air.
H2O – Water, oxidane
Other names: Water (H2O), Hydrogen hydroxide (HH or HOH), Hydrogen oxide
Appearance: White crystalline solid, almost colorless liquid with a hint of blue, colorless gas
2 + 2 HCl → ZnCl2 + 2 H2O – Balanced equation){kind=link}