NEET Chemistry Questions: Basic Principles of Orgainc Chemistry

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Which type of bond can carbon form?





Carbon can form covalent bonds. A covalent bond is a chemical bond that involves the sharing of electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs, and the stable balance of attractive and repulsive forces between atoms, when they share electrons, is known as covalent bonding. Carbon typically forms four covalent bonds to achieve a full outer shell of electrons, which is known as a stable octet.

Why carbon cannot form $ C ^{ +4} $  or $ C^{-4} $ ion?





Carbon cannot form $ C^{+4} $ or $ C^{-4} $ ions mainly due to the high ionization enthalpy and high electron gain enthalpy required. Ionization enthalpy refers to the energy required to remove electrons, and for carbon to lose four electrons, it would require a very high amount of energy. Similarly, electron gain enthalpy is the energy change when an electron is added to an atom. Adding four electrons to carbon would also require a significant amount of energy, making it highly unfavorable. Therefore, both high ionization enthalpy and high electron gain enthalpy prevent the formation of $ C^{+4} $ or $ C^{-4} $ ions.
In which state C can show tetra valency ?




Carbon shows tetravalency in its excited state. In its ground state, carbon has the electronic configuration $1s^2 2s^2 2p^2$. In the excited state, one of the 2s electrons is promoted to the 2p orbital, resulting in the configuration $1s^2 2s^1 2p^3$. This allows carbon to form four covalent bonds, utilizing one electron from the 2s orbital and three electrons from the 2p orbitals, making it tetravalent.
Which molecule all the least C-C distance ?




In organic chemistry, C-C bond lengths depend on the type of bond between the carbon atoms. In $C_2H_2$ (acetylene), the carbon atoms are connected by a triple bond, which is shorter than double bonds (found in $C_2H_4$) and single bonds (found in $C_2H_6$ and $C_4H_8$). Therefore, $C_2H_2$ has the shortest C-C distance.
What is the value of C – C bond length in ethyne ?




No explanation available.
In $ C_6H_6 and C_2H_4$ , the 3H - C - H and are respectively __________




In benzene ($C_6H_6$), each carbon is sp2 hybridized, leading to bond angles of $120^ ext{°}$. Similarly, in ethene ($C_2H_4$), the carbons are also sp2 hybridized, resulting in bond angles of $120^ ext{°}$ around each carbon atom.
The compound in which carbon uses only its sp3 hybrid orbitals for bond formation is




The compound $ (CH_3)_3 COH $ (tert-butyl alcohol) involves carbon atoms that are all sp^3 hybridized. In this structure, each carbon forms four sigma bonds, which is characteristic of sp^3 hybridization. The central carbon is bonded to three methyl groups and one hydroxyl group, utilizing sp^3 hybrid orbitals for all its bonds.
When the hybridization state of carbon changes from $sp^3 to sp^2$ and finally to sp, the angle between the hybridized orbitals




When the hybridization state of carbon changes from $sp^3$ to $sp^2$ and finally to $sp$, the bond angles increase progressively. In $sp^3$ hybridization, the bond angles are approximately 109.5°. In $sp^2$ hybridization, the bond angles are 120°, and in $sp$ hybridization, the bond angles are 180°. This increase in bond angle is due to the increasing s-character in the hybrid orbitals.
What is the general formula of Homologus series




No explanation available.
In homologus series what is the difference in amu?




In a homologous series, each successive member differs by a -CH2- group. The molecular weight of a -CH2- group is 14 amu (12 for carbon and 2 for hydrogen). Therefore, the difference in atomic mass units (amu) between consecutive members of a homologous series is 14.
As number of C atom in homologus series increases Then which of the following will increases?




No explanation available.
Which of the following exist in gas and liquid State?




No explanation available.
Among the following, which is not an example of a homologous series ?




A homologous series is a group of organic compounds that have a similar general formula, similar chemical properties, and successive members differ by a CH2 unit. Option o4 includes $CH_3COOH$ (acetic acid), $CH_3COOCH_3$ (methyl acetate), and $CH_3COOCH_2CH_3$ (ethyl acetate), which do not fit the criteria of a homologous series because they belong to different functional groups (carboxylic acid and esters).
In homologous series :




In a homologous series, the compounds share a general formula. For example, alkanes have the general formula $C_nH_{2n+2}$, alkenes have $C_nH_{2n}$, and alcohols have $C_nH_{2n+1}OH$. This general formula helps in predicting the molecular formula of the compounds in the series.

Which of the following is the first member of ester homologous series ?