NEET Practice Questions (MCQs) with Answers & Solutions

The context specifies: 'Aryl chlorides and bromides can be easily prepared by electrophilic substitution of arenes with chlorine and bromine respectively in the presence of Lewis acid catalysts like iron or iron(III) chloride.'

The context states: 'Fluoro compounds are not prepared by this method due to high reactivity of fluorine.'

The context mentions: 'Replacement of the diazonium group by iodine does not require the presence of cuprous halide and is done simply by shaking the diazonium salt with potassium iodide.'

The context explicitly states: 'The above methods are not applicable for the preparation of aryl halides because the carbon-oxygen bond in phenols has a partial double bond character and is difficult to break being stronger than a single bond.'

The context mentions: 'Propene yields two products, however only one predominates as per Markovnikov’s rule.' (Unit 13, Class XI), which implies that the halogen adds to the carbon atom of the double bond that has the greater number of alkyl substituents (or fewer hydrogen atoms).

The context describes: 'addition of bromine in CCl4 to an alkene resulting in discharge of reddish brown colour of bromine constitutes an important method for the detection of double bond in a molecule.'

The context states: 'Two biologically active compounds, namely adrenaline and ephedrine, both containing secondary amino group, are used to increase blood pressure.' Novocain is an anesthetic, Benadryl is an antihistaminic with a tertiary amino group, and quaternary ammonium salts are surfactants.

The NCERT text explicitly mentions: 'Like ammonia, nitrogen atom of amines is trivalent and carries an unshared pair of electrons. Nitrogen orbitals in amines are therefore, $sp^3$ hybridised and the geometry of amines is pyramidal.'

The context states: 'On the other hand, aromatic amines are weaker bases than ammonia due to the electron withdrawing nature of the aryl group.' The other options are correctly stated in the provided text.

The text states: 'Therefore, the order of boiling points of isomeric amines is as follows: Primary > Secondary > Tertiary.' This is due to the extent of intermolecular hydrogen bonding, being highest in primary amines and absent in tertiary amines.