Perchloric acid (HClO4) is a strong mineral acid with a pKa of −15.2±2.0. It forms stable azeotrope with water containing about 72.5% perchloric acid. Can be prepared from potassium or barium perchlorate solutions
Propionaldehyde (CH3CH2CHO) is a colorless, flammable liquid with fruity odor. Produced industrially by hydroformylation of ethylene. Exists in equilibrium with 1,1-propanediol in water
Calcination is thermal treatment of compounds at high temperatures without melting. Process removes impurities and volatile substances under controlled oxygen. Most common application is limestone calcination to produce quicklime. Calciner rotates in heated furnace at 550-1150°C
AlCl3 forms hexahydrate with formula [Al(H2O)6]Cl3. Anhydrous form is colourless, often contaminated with iron(III) chloride. Solid form has sheet-like layered structure with cubic chloride ions. Melts as dimer Al2Cl6, then decomposes into monomer at high temperatures
Copper(II) chloride exists as yellowish-brown anhydrous form and blue-green dihydrate. Anhydrous form adopts distorted cadmium iodide structure with octahedral copper centers. Compound is paramagnetic and used in first electron paramagnetic resonance measurements
Hydrochloric acid is a colorless solution of hydrogen chloride. It is classified as a strong acid with a pungent smell. The pKa value in aqueous solution is approximately -5.9