Concepts of acids and bases

Concepts of acids and bases : Hard-Soft acid base concept, Non-aqueous solvents.

YEAR JUN-2016 DEC-2015 JUN-2015 DEC-2014 JUN-2014 DEC-2013 JUN-2013 DEC-2012 JUN-2012 DEC-2011 JUN-2011
No.of questions appeared 1   – 4 1 2 7 1 1 2 2 1

1.In the reactions (A) and (B), 

nH2O + Cl [Cl(H2O)n]–                               … (A)

6H2O + Mg2+[Mg (H2O)6] 2+                           … (B)

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)

 

2.In the following reactions carried out in liquid NH3.

Zn(NH2)2+ 2KNH2  →  K2[Zn( NH2)4]

K2[Zn( NH2)4]+ 2NH4NO3 → Zn(NH2)2 + 2KNO3+4NH3

KNH2  and NH4NO3  act respectively as

(a) Solvo-acid and solvo-base

(b) Solvo-base and solvo-acid

(c) Conjugate acid and conjugate base

(d) Conjugate base and conjugate acid

 

3.Match each item from the List-I (compound in solvent) with that from the List-II (its behaviour) and select thecorrect combination using the codes given below.

         List-I                                                      List-II

  1. CH3COOH in pyridine                  (i) strong acid.
  2. CH3COOH in H2SO4                    (ii) weak acid
  3. HClO4in H2SO4                            (iii) strong base
  4. SbF5 in HF                                     (iv) weak base

(1) (A–i), (B–ii), (C–iii), (D–iv)

(b) (A–ii), (B–i), (C–iii), (D–iv)

(c) (A–iii), (B–iv), (C–ii), (D–i)

(d) (A–iv), (B–ii), (C–iii), (D–i)

 

4.The reaction between SbF5 and two equivalents of HF leads to the formation of

 (a) H2SbF3+ 2F2

(b) HSbF2+ 3F2

(c) SbF3+ H2 + 2F2

(d) [SbF6 ]+[H2F]+

 

5.Among the following species, (A) Ni(II) as dimethylglyoximate, (B) Al(III) as oxinate, (C) Ag(I) as chloride,those that precipitate with the urea hydrolysis method are

(a) A, B and C

(b) A and B

(c) A and C

(d) B and C

 

6.The particles postulated to always accompany the positron emission among

(A) neutrino, (B) anti-neutrino, (C) electron,are

(a) A, B and C

(b) A and B

(c) A and C

(d) B and C

 

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