Chemistry

Bleaching powder primarily contains chlorine, which is responsible for its bleaching and disinfecting properties. The other elements listed are not components of bleaching powder.

Oil of vitriol is the historical name for sulfuric acid, a dense, oily liquid widely used in industry and laboratories.

Sodium thiosulphate is commonly used as a fixer in photography to dissolve unexposed silver halide crystals from the photographic film or paper, making the image permanent and light-resistant.

Tungsten has the highest melting point among natural elements, at about 3422°C, which is significantly higher than iron, copper, or silver. This makes it the correct answer.

Ruby is a red gemstone that is primarily composed of aluminum oxide (Al2O3), which is the mineral corundum. The red color of ruby is due to trace amounts of chromium replacing some aluminum atoms in the crystal structure. It is not an oxide of gold, silver, or platinum. Therefore, the correct answer is D, aluminium oxide.

Dmitri Mendeleev is credited with creating the periodic table by arranging elements according to their atomic masses and properties, which allowed him to predict undiscovered elements.

Natural gas, petroleum, and coal primarily consist of hydrocarbons, which are compounds made mostly of carbon atoms. Carbon forms the major part of these fossil fuels, making option A correct. Methane is a component of natural gas but not the major part of all three substances.

The reaction between methane and chlorine in diffused sunlight proceeds via a radical substitution mechanism, where chlorine radicals replace hydrogen atoms in methane.

Glycerol (also known as glycerin) is the alcohol used in the preparation of dynamite. It is nitrated to form nitroglycerin, the explosive compound in dynamite. The other alcohols listed are not used in this process.

The chemical symbol for Gold is 'Au', derived from its Latin name 'Aurum'. This is the standard symbol used in the periodic table.