At a given temperature the K_c for the reaction,

PCl₅ (g) $\rightleftharpoons$ PCl₃ (g) + Cl₂ (g) is 2.4 x10^-3. At the same temperature, the K_c for the reaction

PCl₃ (g) + Cl₂ (g) $\rightleftharpoons$ PCl₅ (g)  is :

1. 2.4x10^-3           

2. -2.4 x10^-3

3. 4.2 x10²           

4.  4.8 x10^-2

HI was heated in a sealed tube at 440$°$C till the equilibrium was reached. At this point, HI was found to be 22 % decomposed. The equilibrium constant for this dissociation is :

28 g N₂ and 6g H₂ were mixed. At equilibrium 17 g NH₃ was formed. the mass of N₂ and H₂ of equilibrium are respectively:

1. 11 g, zero                             

2. 1 g, 3 g

3. 14 g, 3 g                                 

4. 11 g, 3 g

The strongest acid among the following is:          

1. H₂SO₄           

_2. HClO₃       

3. HClO₄         

4. H₂SO₃ 

pH for the solution of salt undergoing anionic hydrolysis (say CH₃COONa) is given by:

1. pH = $\frac{1}{2}$[pK_w + pK_a + log c]

2. pH = $\frac{1}{2}$[pK_w + pK_a - log c]

3. pH = $\frac{1}{2}$[pK_w + pK_b - log c]

4. none of the above

Which can act as an acidic buffer?

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