Chemistry

The NCERT Exemplar questions go beyond the textbook questions as they are designed to be more challenging and conceptually advanced. Practicing the NCERT exemplar provides a better understanding of complex topics like conductance and electrochemical cells. It also helps in better preparation for the entrance exams. The exemplar often involves multi-concept, application-based, and analytical problems.

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Because energy is required to overcome the attractions between the haloalkane molecules as well as to break the hydrogen bonds between water molecules in order to dissolve a haloalkane in water, haloalkanes are only weakly soluble in water. New attractions between the haloalkane and the water molecules, on the other hand, release less energy since they are weaker than the water's initial hydrogen bonds.

This is a short answer type question as classified in NCERT Exemplar

This addition reaction is carried out in accordance with Markovnikoff's rule, which states that in a double bond, the hydrogen from the hydrogen halide is added to the carbon atom with the most hydrogen atoms attached to it, while the halogen atom is attached to the carbon atom with the fewest hydrogens attached to it. The main product in the combination will be the molecule that follows this guideline. As a result, the molecule (B) will be the reaction's main product.

A salt bridge in a galvanic cell maintains electrical neutrality by allowing the ions to flow between the two half-cells. It ensures the continuous flow without participating in the reaction. The salt bridge prevents the charges accumulation as such an accumulation can halt the electrochemical reaction by stopping the flow of electrons.

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(a) Br₂ gas is produced when NaBr and H₂SO₄ are combined. Because of the stable molecule created as a result of resonance stabilisation, molecule

(b) Will not react with Br₂ gas.

The Nernst equation in Electrochemistry is important because, under non-standard conditions, it allows us to calculate the electrode potential of the half and full cell. This equation shows how the potential of the cell varies with the temperature, concentration, and pressure. In electrochemical cells, it helps in predicting the spontaneity and direction of redox reactions.

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In the presence of Lewis acid catalysts (iron or iron chloride), aryl bromides and chlorides can be made by electrophilic replacement of arenas with bromine and chlorine, respectively.

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The resonance stabilisation of the aryl ring is the main reason haloarenes are less reactive than haloalkanes and haloalkenes. The electron pairs on the halogen atom, for example, are conjugated with the ring's -electrons in C₆H₅ - Cl. The C-Cl link takes on a partial double bond character as a result of resonance, making it less reactive to nucleophilic substitution than haloalkanes and haloalkanes.

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Triiodomethane is the chemical name for iodoform. Because of its ability to liberate free iodine, it has antibacterial properties.

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In an S_N¹ reaction with the OH ion, C₆H₅−CH₂−Cl will react quicker. This is owing to the carbocation's stability in the compound. The C₆H₅ group is already stable owing to resonance, and the CH₂ attached will receive that stability after the cleavage in the first stage of the S_N1 reaction, resulting in a stable C₆H₅CH₂⁺ carbocation. CH₃-CH₂-Cl does not have the same sort of carbocation.