This is an acid-base reaction (neutralization): K2O is a base, H2SO4 is an acid.
Reactants:
K2O – Potassium oxide, Potassium oxidopotassium
Other names: Potash, Dipotassium oxide, Dipotassium monoxideK2O, Potassium monoxide
Appearance: Pale yellow solid ; Grey hygroscopic crystalline powder
H2SO4 – Sulfuric acid
Other names: Oil of vitriol, Sulfuric acid, concentrated (> 51% and < 100%), H2SO4Sulphuric acid, Battery acid, Hydrogen sulfate, [SO2(OH)2], [S(OH)2O2], Sulfuric acid (aqueous)
Appearance: Clear, colorless liquid ; Odourless colourless oily hygroscopic liquid ; Colorless to dark-brown, oily, odorless liquid. [Note: Pure compound is a solid below 51°F. Often used in an aqueous solution.]