2 mole of PCl₅ were heated in a closed vessel of 2 litre capacity. At equilibrium 40% of PCl₅ dissociated into PCl₃ and Cl₂. The value of the equilibrium constant is :

1. 0.267

2. 0.53

3. 2.63

4. 5.3

Given, HF + H₂O$\stackrel{K_{\mathit{a}}}{\to }$H₃O⁺ + F^-

          F^- + H₂O $\stackrel{K_b}{\to }$HF + OH^-

which relation is correct?

1. K_b =K_w                       

2. K_b =1/K_w 

3. K_a x K_b =K_w                 

4.  K_a/K_b = K_w 

The value sf K_p1 and K_p2 for the reactions

              X$\rightleftharpoons$Y+Z                                          ....(1)

   and      A$\rightleftharpoons$2B                                          ......(2)

are in the ratio 9:1. If the degree of dissociation of X and A be equal, then total pressure at equilibrium (1) and (2) are in the ratio:

1. 1:9                                     

2. 36:1

3. 1:1                                     

4. 3:1

The relation for calculating pH of a solution containing weak acid and its salt is:

1. pH = pK_a + log$\frac{[\mathrm{Conjugate} \mathrm{Base}]}{\left[\mathrm{Acid}\right]}$

2. pH = pK_a - log$\frac{[\mathrm{Conjugate} \mathrm{Base}]}{\left[\mathrm{Acid}\right]}$

3. pH = pK_a + log$\frac{[\mathrm{Conjugate} \mathrm{Base}]}{\left[\mathrm{Salt}\right]}$

4. pOH = pK_a - log$\frac{\left[\mathrm{Acid}\right]}{[\mathrm{Conjugate} \mathrm{Base}]}$

The equilibrium constants for the reaction,

A₂ $\rightleftharpoons$2A at 500 K and 700 K are 1x10^-10 and 1x10^-5. The given reaction is                  

(a) exothermic                    (b) slow

(c) endothermic                  (d) fast

1. a,b

2.c,b

3.a,d

4 c,d

For the chemical reaction, $3\mathrm{X}\left(\mathrm{g}\right) + \mathrm{Y}\left(\mathrm{g}\right) \rightleftharpoons {\mathrm{X}}_3\mathrm{Y}\left(\mathrm{g}\right)$;

the amount of X₃Y at equilibrium is affected by :

1. Temperature and pressure

2. Temperature only

3. Pressure only

4. Temperature, pressure and catalyst

H₂S gas when passed through a solution of cations containing HCl precipitates the cations of the second group in qualitative analysis but not those belonging to the fourth group. It is because: 
 

The equilibrium constant Br₂ $\rightleftharpoons$2Br at 500 K and 700 K are 10^-10 and 10^-5 respectively. The reaction is:

(a) endothermic                                  (b) exothermic

(c) fast                                               (d) slow

1. a,b

2.c,b

3.a,d

4 c,d

Solubility of a gas in liquid increases on:

1. Addition of a catalyst

2. Increasing the pressure

3. Decreasing the pressure

4. Increasing the temperature

A solution is called saturated if:

1. ionic concentration product < solubility product

2. ionic concentration product > solubility product

3. ionic concentration product $\ge$ solubility product

4. none of the above