This option is correct because gypsum is an ore of calcium. It is not an ore of magnesium.

This option is correct because silica gel and gelatin liquify on shaking, changing into the corresponding sol. The sol, when left undisturbed for some time, reverses back to the gel. This phenomenon of reversible sol-gel transformation is called thixotropy.

This option is correct because a colloidal system in which dispersed phase is liquid and dispersion medium is solid, is known as gel.

This option is correct because when  Na₂O₂ is treated with absolute alcohol at 0⁰C,  a white powder of sodium hydrogenperoxide is formed.

This option is correct as two sols of opposite charges when mixed together in equivalent amount, get precipitated. This precipitation is called as mutual coagulation.

This option is correct. The carbonyl compounds have at least one alpha-hydrogen atom. So, formaldehyde does not give aldol condensation.

This option is correct because at high temperature, sodium metaphosphate combines with coloured metal oxide (cuperous oxide) to give sodium cupric phosphate.

This option is correct because certain solutions have lowest vapour pressure and maximum boiling point. Such a solution is formed by decreasing the volume and evolution of heat. Both the solutions have negative deviation.

This option is correct because certain composition of this non-ideal solution shows positive deviation, the vapour pressure of the solution is the highest and its boiling point is lowest. Such non-ideal solutions show the minimum boiling point of azeotropes.

This option is correct because Jone's reagent is the solution of chromium trioxide in diluted sulphuric acid. This reagent is prepared from soduim dichromate and potassium dichromate,  which is especially used for the oxidation of secondary alcohol to ketones and primary alcohol, and then into carboxlyic acid and in few cases into aldehydes.

This option is correct because when KI is added to copper sulphate solution, white precipitate of cuprous iodide is formed and iodine is librated out.

This option is correct because aspartic acid acid contains one amino acid group and two carboxyl group while arginine contain two amino acid and one carboxyl group.

This option is correct because water gas can be used to prepare methyl alcohol industrially in the presence of ZnO + Cr₂O₃ + CuO at 400-450⁰C.

This option is correct because sodium sulphate boils with flower of sulphur to form sodium thiosulphate.

This option is correct because cobalt nitrate on heating at high temperature with zinc oxide produces cobalt zincate. This is called as Rinmann's green.