This is an acid-base reaction (neutralization): Cu(OH)2 is a base, HNO3 is an acid.
Reactants:
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Cu(OH)2 – Copper(II) hydroxide
Other names: Cupric hydroxide, Cu(OH)2
Appearance: Blue or blue-green solid
HNO3 – Nitric acid
Other names: Aqua fortis, Spirit of niter, Eau forte
Appearance: Colorless, yellow or red fuming liquid ; Colourless-to-yellow liquid with pungent odour ; Colorless, yellow, or red, fuming liquid with an acrid, suffocating odor. [Note: Often used in an aqueous solution. Fuming nitric acid is concentrated nitric acid that contains dissolved nitrogen dioxide.]
Products:
Cu(NO3)2 – Copper(II) nitrate
Other names: Cupric nitrate, Nitrato de cobre (II), Нитрат меди (II) (безводный)
Appearance: Blue crystals | hygroscopic
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