Equivalent amounts of H₂ and I₂, are heated in a closed vessel till equilibrium is obtained. If 80% of the hydrogen can be converted to HI, the K_c at this temperature is :

• 64

• 16

• 0.25

• 4

For the reaction ${\mathrm{H}}_2\left(\mathrm{g}\right) + {\mathrm{I}}_2\left(\mathrm{g}\right) \to 2\mathrm{HI}\left(\mathrm{g}\right),$ the equilibrium constant K_P changes with: 

• total pressure

• catalyst

• the amount H₂ and I₂

• temperature

In a closed container, a liquid is stirred with a paddle to increase the temperature. Which of the following is true ?

• $∆\mathrm{E} = \mathrm{W} \ne 0, \mathrm{q}= 0$

• $∆\mathrm{E} = \mathrm{W} =\mathrm{q} \ne 0$

• $∆\mathrm{E} =0, \mathrm{W} = \mathrm{q}\ne 0$

• $\mathrm{W} =0, ∆\mathrm{E}= \mathrm{q}\ne 0$

If an allotropic form changes slowly to a stable form. It is called

• enantiotropy

• dynamic allotropy

• monotropy

• None of the above

The pH of a buffer solution containing equal molal concentration of a weak base and its chloride (K_b for weak base = 2 x 10^-5) is 

• 5

• 9

• 4.7

• 9.3

Consider the following equilibrium in a closed container

        ${\mathrm{N}}_2{\mathrm{O}}_4\left(\mathrm{g}\right) \rightleftharpoons 2{\mathrm{NO}}_2\left(\mathrm{g}\right)$

At a fixed temperature, the volume of the reaction container is halved. For this change which of the following statement holds true regarding the equilibrium constant (K_p) and degree of dissociation ($\mathrm{\alpha }$)?

• Neither K_P nor $\mathrm{\alpha }$ changes

• Both K_p and $\mathrm{\alpha }$ changes

• K_p changes but $\mathrm{\alpha }$ does not

• K_p does not change but $\mathrm{\alpha }$ changes

Conjugate acid ${\mathrm{S}}_2{\mathrm{O}}_8^{2-}$

• H₂S₂O₈

• H₂SO₄

• HS₂${\mathrm{O}}_8^{-}$

• HS${\mathrm{O}}_4^{-}$

The equilibrium constant of a reaction is 300. If the volume of reaction flask is tripled, the equilibrium constant is

• 300

• 600

• 900

• 100

A 0.01 M ammonia solution is 5% ionised, its pH will be

• 11.80

• 10.69

• 7.22

• 12.24

90.

The pH of a 10^-8 molar solution of HCl in water is

• 8

• between 7 and 8

• between 6 and 7

• None of these