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Which property of amino acids leads to their amphoteric behavior?
The NCERT Chemistry text explains, 'In zwitter ionic form, amino acids show amphoteric behaviour as they react both with acids and bases.' This behavior arises from the presence of both acidic and basic groups.
Palmitic acid has 16 carbons. How many carbons does its R group contain, excluding the carboxyl carbon?
The NCERT Biology text states, 'A fatty acid has a carboxyl group attached to an R group... Palmitic acid has 16 carbons including carboxyl carbon.' Therefore, the R group contains $16 - 1 = 15$ carbons.
Haloarenes contain a halogen atom attached to which type of hybridised carbon atom?
Haloarenes contain a halogen atom(s) attached to sp$^2$ hybridised carbon atom(s) of an aryl group.
Which of the following influences the polarity of the C-X bond?
Halogen atoms are more electronegative than carbon, therefore, carbon-halogen bond of alkyl halide is polarised. This electronegativity difference is the primary factor influencing the polarity.
How does the s-character of the carbon hybrid orbital in the C-X bond affect its strength in haloarenes compared to haloalkanes?
The sp$^2$ hybridised carbon with a greater s-character (in haloarenes) is more electronegative and can hold the electron pair of the C-X bond more tightly than sp$^3$-hybridised carbon (in haloalkanes) with less s-character. This results in a stronger and shorter bond in haloarenes.
What is the consequence of the C-X bond acquiring partial double bond character in haloarenes regarding bond cleavage?
C-Cl bond acquires a partial double bond character due to resonance. As a result, the bond cleavage in haloarene is difficult than haloalkane and therefore, they are less reactive towards nucleophilic substitution reaction.
Which of the following describes the electron distribution around the internuclear axis of a C-C sigma bond in alkanes?
As per the NCERT text, 'Electron distribution of the sigma molecular orbital is symmetrical around the internuclear axis of the C–C bond which is not disturbed due to rotation about its axis.' This symmetry allows for free rotation. (Chapter: Hydrocarbons, Page 305)
The rotation around a C-C single bond in alkanes is not completely free due to a weak repulsive interaction between adjacent bonds, known as:
The context states: 'rotation around a C-C single bond is not completely free. It is hindered by a small energy barrier of 1-20 kJ mol–1 due to weak repulsive interaction between the adjacent bonds. Such a type of repulsive interaction is called torsional strain.' (Chapter: Hydrocarbons, Page 305)
How many conformations can alkanes theoretically have by rotation around C-C single bonds?
The NCERT text explicitly states: 'Alkanes can thus have infinite number of conformations by rotation around C-C single bonds.' (Chapter: Hydrocarbons, Page 305)
In the ethane molecule ($C_2H_6$), which conformation has the hydrogen atoms attached to the two carbons as closed together as possible?
The NCERT states: 'One such conformation in which hydrogen atoms attached to two carbons are as closed together as possible is called eclipsed conformation...' (Chapter: Hydrocarbons, Page 305)
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