This is an acid-base reaction (neutralization): KOH is a base, H2SO4 is an acid.
KOH – Potassium hydroxide
Other names: Caustic potash, Lye, Potash lye
Appearance: White solid, deliquescent ; White hygroscopic solid in various forms ; Odorless, white or slightly yellow lumps, rods, flakes, sticks, or pellets. [Note: May be used as an aqueous solution.]
H2SO4 – Sulfuric acid
Other names: Oil of vitriol, Sulfuric acid, concentrated (> 51% and , H2SO4
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.]