This is an acid-base reaction (neutralization): KHCO3 is a base, HCl is an acid.
This is a gas evolution reaction, CO2 is the formed gas.
Reactants:
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KHCO3 – Potassium hydrogen carbonate
Other names: Potassium bicarbonate, Potassium acid carbonate, KHCO3
Appearance: White crystals
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:
KCl
Names: Potassium chloride, Sylvite, Muriate of potash
Appearance: White crystalline solid ; Colourless hygroscopic crystals
CO2
Names: Carbon dioxide, {{plainlist|, CO2
Appearance: Colorless gas ; Odourless colourless compressed liquefied gas ; Colorless, odorless gas. [Note: Shipped as a liquefied compressed gas. Solid form is utilized as dry ice.]
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