Q1 · CSIR NET Chemistry, June 2012
Paper: CSIR NET June 2012 · Subject: Inorganic Chemistry · Chapter: Acid and Bases · Topic: Lewis Bronsted · Marks: 2 · Difficulty: Medium
In the reactions (A) and (B),
\[ \begin{array}{l} \mathrm{n(H_2O)} + \mathrm{Cl^-} \rightarrow [\mathrm{Cl(H_2O)_n}]^{-} \quad \text{..... (A)} \\ \mathrm{(H_2O)_6} + \mathrm{Mg^{2+}} \rightarrow [\mathrm{Mg(H_2O)_6}]^{2+} \quad \text{...... (B)} \end{array} \]
water behaves as(a)An acid in both (A) and (B)
(b)An acid in (A) and a base in (B)
(c)A base in (A) an acid in (B)
(d)A base in both (A) and (B)
Answer
Answer: B ✓ checked by 4AB · confidence high
Explanation
In (A) the H end of water's O–H dipole turns towards Cl⁻ and hydrogen-bonds to it: water is the electron-pair acceptor (an acid). In (B) water donates a lone pair to Mg²⁺ as a ligand: a Lewis base. So water is an acid in (A) and a base in (B).
Study loop for Acid and Bases