JNTU Pharm. D I Year PHARMACEUTICAL ORGANIC CHEMISTRY Previous Question Paper (January - 2022 - R08)

The Bronsted-Lowry theory defines an acid as a proton (H+) donor and a base as a proton acceptor. This theory emphasizes the transfer of protons in acid-base reactions, resulting in the formation of conjugate acid-base pairs. For example, in the reaction between HCl and H2O, HCl acts as the acid by donating a proton to H2O, which acts as the base.

The Lewis theory defines an acid as an electron pair acceptor and a base as an electron pair donor. This theory is broader than the Bronsted-Lowry theory as it does not require the presence of hydrogen. A Lewis base (nucleophile) shares a lone pair of electrons with a Lewis acid (electrophile) to form a coordinate covalent bond. An example is the reaction between boron trifluoride (BF3) and ammonia (NH3), where NH3 donates its lone pair to the electron-deficient boron atom.

i) Ketones: The IUPAC nomenclature for ketones involves identifying the longest carbon chain containing the carbonyl group. The suffix '-e' of the corresponding alkane is replaced with '-one'. The chain is numbered starting from the end closest to the carbonyl group to ensure it receives the lowest possible locant. If multiple ketones are present, prefixes like 'di-' or 'tri-' are used before the '-one' suffix.

ii) Carboxylic acids: The IUPAC nomenclature for carboxylic acids involves identifying the longest carbon chain that includes the carboxyl carbon (C1). The suffix '-e' of the corresponding alkane is replaced with '-oic acid'. The carboxyl carbon is always assigned position 1. If the carboxyl group is attached to a ring, the suffix 'carboxylic acid' is added to the name of the cyclic alkane.