Carbon and its Compound (NCERT 10th Class short Notes)

·         Unsaturated hydrocarbons add hydrogen in the presence of catalysts such as palladium or nickel to give saturated hydrocarbons.

·         This reaction is commonly used in the hydrogenation of vegetable oils using a nickel catalyst.

·           Vegetable oils generally have long unsaturated carbon chains while animal fats have saturated carbon chains.

·         Animal fats generally contain saturated fatty acids.

·         Oils containing unsaturated fatty acids should be chosen for cooking.

·         Ethanol (CH₃CH₂OH)

-          liquid at room temperature

-          melting point = 156K

-          boiling points = 351K

-          commonly called alcohol

-          active ingredient of all alcoholic drinks.

-          also used in medicines such as tincture iodine, cough syrups, and many tonics.

-          soluble in water

·         Intake of methanol in very small quantities can cause death. Methanol is oxidised to methanal in the liver. Methanal reacts rapidly with the components of cells. It causes the protoplasm to get coagulated, in much the same way an egg is coagulated by cooking. Methanol also affects the optic nerve, causing blindness

·         Sugarcane juice can be used to prepare molasses which is fermented to give alcohol (ethanol). Some countries now use alcohol as an additive in petrol since it is a
cleaner fuel which gives rise to only carbon dioxide and water on burning in sufficient air (oxygen)

·         Ethanoic Acid (Acetic Acid)

-          Ethanoic acid is commonly called acetic acid

-          belongs to a group of acids called carboxylic acids.

-          5-8% solution of acetic acid in water is called vinegar and is used widely as a preservative
in pickles.

-           The melting point of pure ethanoic acid is 290 K

-          This gave rise to its name glacial acetic acid

·         Esterification reaction: Esters are most commonly formed by reaction of an acid and an alcohol.
Ethanoic acid reacts with absolute ethanol in the presence of an acid catalyst to give an ester. Esters are sweet-smelling substances. These are used in making perfumes and as flavouring agents.

·         Esters react in the presence of an acid or a base to give back the alcohol and carboxylic acid. This
reaction is known as saponification because it is used in the preparation of soap.

·         Reaction with carbonates and hydrogencarbonates: Ethanoic acid reacts with carbonates and hydrogencarbonates to give rise to a salt, carbon dioxide and water. The salt produced is commonly called sodium acetate.

·         Reaction with a base: Like mineral acids, ethanoic acid reacts with a base such as sodium hydroxide to give a salt (sodium ethanoate or commonly called sodium acetate) and water.

·         Detergents are generally ammonium or sulphonate salts of long chain carboxylic acids.

·         The molecules of soap are sodium or potassium salts of long-chain carboxylic acids. The ionic-end of soap dissolves in water while the carbon chain dissolves in oil.

·         Carbon exists in the atmosphere in the form of carbon monoxide in traces and carbon dioxide.

·         Carbon compounds: are poor conductors of electricity and do not have strong forces of attraction between their molecules.

·         A molecule of ammonia (NH3) has only single bonds.

·         The soap molecule has a hydrophilic head and a hydrophobic tail.

·         Ethanol reacts with sodium and forms two products. These are sodium ethoxide and hydrogen.

·    Mineral acids are stronger acids than carboxylic acids because: mineral acids are completely ionized, carboxylic acids are partially ionized.