Which among the following statements with respect to carbon is/are correct? 1. Carbon forms the basis for all living organisms and many things we use 2. Carbon shows tetra-valency and the property of catenation 3. Carbon forms covalent bonds with itself and other elements 4. Carbon forms compounds containing triple and tetra bonds between carbon atoms Select the correct answer using the code given below:
1, 2 and 3
Understanding the Properties of Carbon
Carbon is a unique element that forms the backbone of organic chemistry and is fundamental to life as we know it. Let's examine each statement provided in the question to determine its correctness regarding the properties of carbon.
Statement 1: Carbon forms the basis for all living organisms and many things we use
This statement is correct. Living organisms are primarily composed of organic molecules, which are compounds based on carbon chains and rings. Furthermore, countless materials we use in our daily lives, such as plastics, fuels, medicines, clothing fibers (like cotton, wool, silk, and many synthetics), and building materials, are organic compounds or derived from them.
Statement 2: Carbon shows tetra-valency and the property of catenation
This statement is correct.
- Tetra-valency: Carbon has an atomic number of 6, with an electronic configuration of $1s^2 2s^2 2p^2$. To achieve a stable octet configuration, it needs to gain or share 4 electrons. Carbon typically forms four covalent bonds, meaning it is tetravalent. These four bonds can be single bonds, or a combination of single, double, and triple bonds.
- Catenation: Catenation is the ability of an element to form bonds with atoms of the same element. Carbon atoms can link together to form long chains, branched chains, rings, and complex network structures. This property is exceptionally strong in carbon and is responsible for the vast diversity of organic compounds.
Statement 3: Carbon forms covalent bonds with itself and other elements
This statement is correct. Due to its electronegativity value (around 2.55 on the Pauling scale), carbon tends to share electrons rather than gain or lose them. This electron sharing leads to the formation of strong covalent bonds. Carbon forms covalent bonds readily with other carbon atoms (as seen in catenation) and with many other elements like hydrogen (H), oxygen (O), nitrogen (N), sulfur (S), halogens (F, Cl, Br, I), etc.
Statement 4: Carbon forms compounds containing triple and tetra bonds between carbon atoms
This statement is partially correct but mostly incorrect. Carbon atoms can form single bonds (C-C), double bonds (C=C), and triple bonds (C≡C) with other carbon atoms. Compounds containing triple bonds are called alkynes. However, carbon does not typically form stable compounds containing a quadruple bond (tetra bond) between carbon atoms (C≡C with an extra bond, which would mean 8 bonds in total, not possible for carbon). While some exotic or transient species might theoretically involve complex bonding scenarios, stable, common carbon compounds do not exhibit carbon-carbon tetra bonds.
Based on the analysis:
- Statement 1 is correct.
- Statement 2 is correct.
- Statement 3 is correct.
- Statement 4 is incorrect regarding tetra bonds.
Therefore, the correct statements are 1, 2, and 3.
| Statement No. | Statement Text | Correctness | Reasoning |
|---|---|---|---|
| 1 | Carbon forms the basis for all living organisms and many things we use | Correct | Basis of organic chemistry and living matter; found in many everyday materials. |
| 2 | Carbon shows tetra-valency and the property of catenation | Correct | Forms 4 covalent bonds (tetravalent); links with other carbon atoms (catenation). |
| 3 | Carbon forms covalent bonds with itself and other elements | Correct | Tends to share electrons due to electronegativity. |
| 4 | Carbon forms compounds containing triple and tetra bonds between carbon atoms | Incorrect | Forms single, double, and triple bonds, but not stable quadruple (tetra) bonds. |
The combination of statements 1, 2, and 3 correctly describes fundamental properties and roles of the carbon element.
Revision Table: Key Carbon Properties
| Property | Description | Significance |
|---|---|---|
| Atomic Number | 6 | Determines electron configuration and bonding. |
| Valency | Tetra-valency (4) | Forms four bonds, allowing diverse structures. |
| Bonding Type | Covalent | Forms stable bonds by sharing electrons. |
| Catenation | Ability to bond with other carbon atoms | Forms chains, rings, branched structures; basis of organic complexity. |
| Common Bonds Formed | Single (C-C), Double (C=C), Triple (C≡C) | Allows for different levels of saturation and reactivity. |
| Role in Life | Backbone of organic molecules | Essential element for all known life forms. |
Additional Information: Why Carbon is Unique
Carbon's unique properties make it central to chemistry and life. Here are some points for deeper understanding:
- Electron Configuration: With $2s^2 2p^2$ valence electrons, carbon can hybridize its orbitals (sp, sp², sp³) to form strong sigma and pi bonds with various geometries (linear, trigonal planar, tetrahedral).
- Bond Strength: Carbon-carbon and carbon-hydrogen covalent bonds are relatively strong and stable, contributing to the stability of organic compounds.
- Variety of Structures: The combination of tetra-valency, strong catenation, and the ability to form multiple bonds (single, double, triple) allows carbon to create an enormous number of different compounds with varying shapes and properties.
- Presence in the Environment: Carbon is a major component of the Earth's atmosphere (as CO₂), oceans (as dissolved CO₂ and carbonates), rocks (as carbonates), and all organic matter. The carbon cycle describes its movement through these different spheres.
- Allotropes of Carbon: Carbon exists in different structural forms called allotropes, such as diamond (a very hard network solid), graphite (a soft, layered structure), fullerenes (spherical molecules), nanotubes (cylindrical structures), and graphene (a single layer of carbon atoms). These allotropes have vastly different physical properties depending on how the carbon atoms are bonded together.
Understanding these fundamental properties of carbon is crucial for studying organic chemistry and biochemistry.
Important Questions from Organic Chemistry
Which of the hydrocarbons are arranged as per the increasing order of their boiling points?
Which one of the following statements is NOT correct?
Which one of the following statements about diamond and graphite is not correct?
Which one of the following cell organelles does NOT possess nucleic acid?
Which one of the following is NOT a synthetic detergent?
