Q.1
In the reaction I− + I2 → I3−, the Lewis acid is ______ .
[ JEE '97, 1]
Q.2
Between Na+ & Ag+ which is a stronger Lewis acid & why ?
[ JEE '97, 2]
Q.3
Select the correct alternative . [JEE'97,1+1] If pKb for fluoride ion at 25° C is 10.83, the ionisation constant of hydrofluoric acid in water at this temperature is : (A) 1.74 × 10−5 (B) 3.52 × 10−3 (C) 6.75 × 10−4 (D) 5.38 × 10−2
Q.4
The solubility of A2X3 is y mol dm–3. Its solubility product is (A) 6 y2 (B) 64 y4 (C) 36 y5
[JEE 97]
(D) 108 y5
Q.5
Which of the following statement(s) is/are correct ? [ JEE '98, 2 ] (A) the pH of 1.0 × 10−8 M solution of HCl is 8 (B) the conjugate base of H2PO4− is HPO42− (C) autoprotolysis constant of water increases with temperature (D) when a solution of a weak monoprotic acid is titrated again a strong base, at half−neutralization point pH = (1/2) pKa .
Q.6
A buffer solution can be prepared from a mixture of (A) sodium acetate and acetic acid in water (B) sodium acetate and hydrochloric acid in water (C) ammonia and ammonium chloride in water (D) ammonia and sodium hydroxide in water.
[JEE 99]
Q.7
The pH of 0.1 M solution of the following salts increases in the order (A) NaCl < NH4Cl < NaCN < HCl (B) HCl < NH4Cl < NaCl < NaCN (D) HCl < NaCl < NaCN < NH4Cl (C) NaCN < NH4Cl < NaCl < HCl
[JEE 99]
Q.8
An aqueous solution of 6.3 g oxalic acid dihydrate is made up to 250 mL. The volume of 0.1 N NaOH required to completely neutralise 10 mL of this solution is [JEE 2001] (A) 40 mL (B) 20 mL (C) 10 mL (D) 4 mL
Q.9
For sparingly soluble salt ApBq, the relationship of its solubility product (Ls) with its solubility (S) is (A) Ls = Sp+q, pp. qq (B) Ls = Sp+q, pp. qp (C) Ls = Spq, pp. qq (D) Ls = Spq, (p.q)p+q [JEE 2001]
Q.10 A solution which is 10 –3 M each in Mn2+, Fe2+, Zn2+ and Hg2+ is treated with 10–16M sulphide ion. If Ksp, MnS, FeS, ZnS and HgS are 10–15, 10–23, 10–20 and 10–54 respectively, which one will precipitate first ? (A) FeS (B) MnS (C) HgS (D) ZnS [JEE 2003] Q.11 HX is a weak acid (Ka = 10–5). It forms a salt NaX (0.1 M) on reacting with caustic soda. The degree of hydrolysis of NaX is (A) 0.01% (B) 0.0001% (C) 0.1% (D) 0.5% [JEE 2004] Q.12 CH3NH2 (0.1 mole, Kb = 5 × 10–4) is added to 0.08 moles of HCl and the solution is diluted to one litre, resulting hydrogen ion concentration is (A) 1.6 × 10–11 (B) 8 × 10–11 (C) 5 × 10–5 (D) 2 × 10–2 [JEE 2005]
21
Page 21 of 24 IONIC EQULIBRIUM
EXERCISE IV