This is an acid-base reaction (neutralization): H2SO4 is an acid, Ca(OH)2 is a base.
Reactants:
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.]
Appearance: White powder ; Colourless crystals or white powder ; White, odorless powder. [Note: Readily absorbs CO2 from the air to form calcium carbonate.]
Products:
H2O – Water, oxidane
Other names: Water (H2O), Hydrogen hydroxide (HH or HOH), Hydrogen oxideDihydrogen monoxide (DHMO) (systematic name), Hydrogen monoxide, Dihydrogen oxide, Hydric acid, Hydrohydroxic acid, Hydroxic acid, Hydrol, Μ-oxido dihydrogen, Κ1-hydroxyl hydrogen(0)
Appearance: White crystalline solid, almost colorless liquid with a hint of blue, colorless gas
CaSO4
Names: Calcium sulfate, Plaster of Paris, DrieriteGypsum, Calcium sulfate (anhydrous), Anhydrous calcium sulfate, Anhydrous gypsum, Anhydrous sulfate of lime, Calcium salt of sulfuric acid, CaSO4, Calcium sulphate, Calcium sulfate anhydrous, Sulfuric acid, calcium salt (1:1), [Note: Gypsum is the dihydrate form and Plaster of Paris is the hemihydrate form.]
Appearance: White solid ; White hygroscopic powder or crystalline powder ; Odorless, white powder or colorless, crystalline solid. [Note: May have blue, gray, or reddish tinge.]