Question

Which of the following statements are correct?
I. The increasing order of covalent character of NaCl, RbCl, MgCl$_2$ is RbCl < NaCl <\ MgCl$_2$
II. The high boiling point of water is due to intramolecular hydrogen bonding
III. H$_2$O has more dipole moment among NH$_3$, H$_2$O, and HF

• A. I, III only
• B. II, III only
• C. (Missing Option)
• D. (Missing Option)

Hint:

Covalent character trend: Fajan's rules → small cation, high charge → more covalent. Boiling point of water → intermolecular H-bonds, not intramolecular. Dipole moment → consider geometry + bond polarity. Check each statement carefully.

Answer 1

The Correct Option is A

• Statement I: True. Covalent character increases with cation charge density → Mg$^{2+}$ > Na$^+$ > Rb$^+$.
• Statement II: False. High boiling point of water is due to intermolecular hydrogen bonding, not intramolecular.
• Statement III: True. H$_2$O dipole moment is highest among NH$_3$, H$_2$O, HF due to bond angles and electronegativity differences.
• Hence correct statements: I and III only.