Which is wrong statement? — p Block Elements Chemistry Question

💡 Solution & Explanation

Step 1: Evaluate the statements: (a) Thermal stability of alkali metal hydroxides indeed decreases from CsOH to NaOH. (b) Bond angles decrease as BF3 (120°) > PF3 (97.8°) > ClF3 (~87.5°). (c) Bond dissociation energy of halogens decreases in the order Cl2 > Br2 > F2 > I2 due to anomalous interelectronic repulsion in the small F2 molecule. Step 2: For statement (d), the strength of intermolecular hydrogen bonding is highly dependent on the number of N-H hydrogen atoms available. Primary amine (CH3NH2) has more hydrogen atoms available for H-bonding than secondary amine ((CH3)2NH), meaning its boiling/melting point is higher than that of the secondary amine. The actual order of melting/boiling points does not match the proposed order in (d). Step 3: Therefore, statement (d) is incorrect, making (d) the correct option.