Common Chemical Compounds and Reactions

Green vitriol is actually ferrous sulphate (FeSO4), not copper sulphate (CuSO4). Copper sulphate is called blue vitriol. The other options are correctly matched: Galena is lead sulphide (PbS), Plaster of Paris is calcium sulphate hemihydrate, and Calomel is mercurous chloride (Hg2Cl2).

Glycerol is used as a sweetening agent in food, in soap manufacturing to improve quality, and in nitroglycerin production. The 'All of the above' option correctly encompasses all these uses.

The dry distillation of calcium acetate with soda lime (NaOH + CaO) produces methane through decarboxylation. Each acetate ion loses CO2 to form a methyl group, which then combines with hydrogen from the reagents to give methane (CH4). This is a classic laboratory method for alkane synthesis.

Permanent hardness of water caused by sulfates can be removed by zeolites through ion exchange. Zeolites exchange sodium ions for calcium and magnesium ions, effectively softening the water. Nitrates don't remove hardness, sulphonates are not water softeners, and 'none of these' is incorrect since zeolites work.

Lead nitrate decomposes on heating (thermal decomposition) to form lead oxide, nitrogen dioxide, and oxygen. This is a chemical change as new substances are formed. Sodium chloride and silica are stable to heat, while platinum wire only undergoes physical change.

Sodium thiosulphate (Na2S2O3) is used as a fixer in photography because it dissolves unexposed silver halide crystals from the developed emulsion, making the image permanent and light-fast. Borax is used as a buffering agent, sodium sulphate is a drying agent, and ammonium persulphate is an oxidizer.

Arsenic oxide is used as a refining agent in glass manufacture to remove air bubbles and improve clarity. It helps eliminate trapped gases during the melting process. Feldspar, potassium carbonate, and soda ash are raw materials, not refining agents.

Soaps are sodium or potassium salts of long-chain fatty acids (like stearic acid, palmitic acid). They are formed by saponification reaction where fats/oils react with alkali. They are not silicates, esters, or glycerol mixtures.

Soaps are sodium or potassium salts of fatty acids, which are monocarboxylic acids (long-chain acids like stearic acid C17H35COOH have one carboxyl group). They are not salts of dicarboxylic or tricarboxylic acids.

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Potassium lauryl sulphate (KC₁₂H₂₅SO₄), is very much similar to sodium lauryl sulphate. Mud soaps are the terms often associated with this detergent. It has a better cleansing action indicated by the presence of potassium ion.

Lithium hexafluorophosphate is an inorganic compound with the formula LiPF₆. This white crystalline powder is used in commercial secondary batteries, an application that exploits its high solubility in nonpolar solvents. Specifically, solutions of lithium hexafluorophosphate in propylene carbonate with dimethoxyethane serves as an electrolyte in lithium batteries.

Strontium carbonate (SrCO₃) is the carbonate salt of strontium that has the appearance of a white or grey powder. It occurs in nature as the mineral strontianite.The most common use is as an inexpensive colorant in fireworks. Strontium and its salts emit a brilliant red color in flame.

Strontium sulphate (SrSO₄) is the sulphate salt of strontium. It is a white crystalline powder and occurs in nature as the mineral celestine. Strontium sulphate is a polymeric material, isostructural with barium sulphate. Crystallized strontium sulphate is utilized by a small group of radiolarian protozoa, called the Acantharea, as a main constituent of their skeleton.

Caesium perchlorate ( CsClO_{4 )} forms white hygroscopic crystals, which are soluble in water and ethanol. CsClO₄ is the least soluble of the alkali metal perchlorates (followed by Rb, K, Li, and Na), a property which may be used for separatory purposes and even for gravimetric analysis.