Which can act as an acidic buffer?

a.	NH4Cl + NH4OH
b.	CH3COOH + CH3COONa
c.	40 mL of 0.1 M NaCN + 20 mL of 0.1 M HCl

1. Both a and b
2. Both b, and c
3. All are buffer solution
4. Both a, and c

The following equilibrium exists in an aqueous solution 

CH₃COOH $\rightleftharpoons$H⁺ + CH₃COO^- . If dilute HCl is added to this solution:

1. the equilibrium constant will increase

2. the equilibrium constant will decrease

3. acetate ion concentration will increase

4. acetate ion concentration will decrease

The solubility product of CuS, CdS and HgS are 10^-31, 10^-44, 10^-54 respectively. The solubility of these sulphides are in the order

1. CdS>HgS> CuS

2. HgS> CdS>CuS

3. CdS>CuS>HgS

4. CuS>CdS>HgS

The hydroxide having the lowest value of K_sp at 25$°$C is:

1. Mg(OH)₂                                     

2. Ca(OH)₂

3. Ba(OH)₂                                       

4. Be(OH)₂

For the reaction, A + B $\rightleftharpoons$C+D, the initial concentration of A and B are equal, but the equilibrium concentration of C is twice that of the equilibrium concentration of A. The equilibrium constant is:

1. 4                       

2. 9

3. 1/4                     

4. 1/9

Solubility of an aqueous solution of Mg(OH)₂ is X mol litre^-1, then its K_sp is:

1. 4X³                           

2. 108X⁵

3. 27X⁴                         

4. 9X

At constant temperature, the equilibrium constant (K_p) for the decomposition reaction. N₂O₄ $\rightleftharpoons$2NO₂ is expressed by,

         K_p = (4x²P)/(1-x²)

where P= pressure, x = extent of decomposition. Which of the following statements is true?

1.  K_p increases with increase of P

2. K_p  increases with increase of  x

3. K_p increase with decrease of x

4. K_p remains constant with change in P of x

An aqueous solution of ammonium acetate is:

1. faintly acidic                     

2. fair acidic

3. faintly alkaline                   

4. almost neutral

The conjugate acid of NH₂^- is                           

1. N₂H₄   

2. N${\mathrm{H}}_4^{+}$   

3. NH₄OH   

4. NH₃

If the concentration of OH^- ions in the reaction,

 Fe(OH)₃(s) $\rightleftharpoons$Fe³⁺(aq) + 3OH^- (aq)

is decreased by 1/4 times, then equilibrium concentration of Fe³⁺ will increase by         

1. 8 times                         

2. 16 times

3. 64 times                       

4. 4 times