Test: Carbon and its Compound - SSC CGL MCQ

Organic compounds are primarily composed of carbon and form the basis of all living organisms. These compounds are essential for various biological processes, including the formation of cell structures, energy production, and the synthesis of biomolecules like proteins, carbohydrates, lipids, and nucleic acids. Carbon's unique ability to form diverse bonds with other elements allows for the vast array of organic compounds found in nature, contributing to the complexity and diversity of life forms.

Inorganic compounds are distinguished from organic compounds by the absence of carbon-hydrogen (C-H) bonds. While organic compounds are characterized by the presence of C-H bonds and are typically associated with living organisms, inorganic compounds lack these bonds and can include a wide range of substances such as salts, metals, minerals, and gases like carbon dioxide and ammonia. Examples of inorganic compounds include sodium chloride (table salt), calcium carbonate (limestone), and sulfuric acid.

Organic compounds are considered the building blocks of life because they are versatile molecules that form the structural basis of cells and participate in essential biological functions. These compounds are involved in processes such as energy production, cell signaling, growth, and reproduction. Their diverse structures allow for the formation of complex biomolecules like DNA, proteins, carbohydrates, and lipids, which are crucial for the functioning and diversity of biological systems.

Covalent bonds are formed by the sharing of electron pairs between atoms. This sharing allows atoms to achieve a more stable configuration by completing their outer electron shells.

Carbon is tetravalent, meaning it can form four bonds by sharing electrons with other atoms. This characteristic allows carbon to form diverse and complex molecules essential for life.

Covalent compounds have low melting and boiling points because they possess weak intermolecular forces. These weak forces are a result of electrons being shared between atoms rather than being transferred, leading to lower energy requirements for breaking these bonds.

Carbon's tetravalency, which means it has four valence electrons, allows it to form bonds with four atoms, including other carbons, hydrogen, oxygen, nitrogen, and sulfur. This property enables carbon to form a wide variety of structures, including long chains, branched chains, and rings, by bonding with other carbon atoms using single, double, or triple covalent bonds.

Unsaturated hydrocarbons exhibit double or triple bonds between carbon atoms. Alkenes are a type of unsaturated hydrocarbon characterized by double bonds, while alkynes are another type characterized by triple bonds. These double or triple bonds give unsaturated hydrocarbons distinct properties compared to saturated hydrocarbons.

The general formula for alkanes, which are saturated hydrocarbons with single bonds between carbon atoms, is C_nH_2n+2. This formula indicates that for every n number of carbon atoms, there are 2_n+2 hydrogen atoms present in the alkane molecule. Alkanes form a homologous series with gradual changes in physical properties as the number of carbon atoms increases.

Saturated hydrocarbons burn with a blue, non-sooty flame. This occurs due to the complete oxidation of these hydrocarbons. The blue color of the flame is indicative of a clean, efficient combustion process where carbon is fully oxidized to carbon dioxide and water vapor, producing a clean flame without soot.

When ethanol reacts with sodium, it produces hydrogen gas. This reaction is often used as a test for ethanol, with the evolution of hydrogen gas being a characteristic observation. The reaction can be represented as follows: 2C2H5OH + 2Na → 2C2H5ONa + H2.

When ethanoic acid reacts with sodium bicarbonate (NaHCO3), it forms sodium acetate, water, and carbon dioxide. This reaction is a type of acid-base reaction where the acid (ethanoic acid) reacts with the base (sodium bicarbonate) to produce salt (sodium acetate), water, and carbon dioxide as evidenced by effervescence or the release of bubbles of carbon dioxide gas.

Soap is effective in cleaning soft water. In soft water, soap molecules can easily form micelles with dirt and grease, facilitating the cleaning process.

The long hydrocarbon chain of soap molecules attaches to dirt, while the ionic (hydrophilic) part remains in water. This interaction helps in forming micelles and dissolving dirt for effective cleaning.

Unlike soap, detergents do not form scum when reacting with hard water. This property makes detergents more suitable for cleaning clothes in areas with hard water, as they can effectively remove dirt and stains without leaving a residue.