Common Chemical Compounds and Reactions

Limestone (calcium carbonate) is the primary ingredient in cement manufacturing. When limestone is heated with clay and gypsum in a kiln, it forms clinker, which is then ground to make cement. The calcium from limestone combines with silicon, aluminum, and iron from clay to form the cement compounds that harden when mixed with water.

Baking powder is sodium bicarbonate (NaHCO3), a white crystalline powder used as a leavening agent in baking. Option A shows the correct chemical formula. The other options are incorrect: NaHCO2 doesn't exist, NaOH is sodium hydroxide (lye), and NaOH3 is not a valid compound.

Plaster of Paris is calcium sulphate hemihydrate (CaSO4·0.5H2O), a white powder that forms a hard paste when mixed with water and then dries. It's called 'Plaster of Paris' because gypsum, the main source material, was abundantly available near Paris.

Chalk is insoluble in water.

Calcium phosphate (hydroxyapatite) is the primary mineral component of vertebrate bones and teeth, providing structural hardness and strength. While bones also contain collagen, the inorganic mineral phase is predominantly calcium phosphate. Sodium chloride is table salt, sugar is organic, and calcium sulfate is gypsum.

Baking soda is sodium bicarbonate (NaHCO3), a leavening agent that releases carbon dioxide when heated or combined with acid. Potassium carbonate is a different compound, NaOH is sodium hydroxide (lye), and NaCO3 is not a stable compound.

This option is correct because the salt cake, when heated with cold limestone dust, gives black ash.

This option is correct because the action of nitric acid on excess lime produces basic calcium nitrate. It is called Norwegian salt.

This option is correct because sodium carbonate and potassium carbonate are comprised in fusion mixture.

This option is correct because sodium silicate is called as water glass.

This option is correct because the crystal of sodium carbonate are exposed to air to form a fine powder in which nine water molecules are exposed to air. It gives monohydrated sodium carbonate. These types of crystal are called as efflorescence.

Agar is more often used solidifying agent in culture media. It melts completely at the temperature of boiling water (97-100^oC) and solidifies when cooled to about 45^oC. It is chemically polysaccharide and is not attacked by bacteria and others microbes growing on it. Agar is obtained from seaweeds(Algae) called kelps.

NaCl is sodium chloride. It is the common salt that we use for cookoing.

It is a mixed salt. Salt that contains more than one acid radical or basic radical is called as mixed salt. Other examples are bleaching powder ;Ca(OCl) and sodium potassium sulphate;NaKSO_4.