Assertion : PCl₅, is covalent in gaseous and  liquid states but ionic in solid state.

Reason : PCl, in solid state consists of tetrahedral PC${\mathrm{l}}_4^{+}$cation and octahedral PC${\mathrm{l}}_6^{-}$ anion.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.

Solubility product of a salt AB is 1 x 10^-8 M in a solution in which the concentration of A⁺ ions is 10^-3 M .The salt , will precipitate when the concentration of B^- ions is kept :

• between 10^-8 M to 10^-7 M

• between 10^-7 M to 10^-8 M

• > 10^-5 M

• < 10^-8 M

The pH of 10^-8 M HCl solution is :

• 8

• more than 8

• between 6 and 7

• slightly more than 7

For a reversible reaction ;

X (g) + 3Y (g) $\rightleftharpoons$ 2Z (g) ; $∆$H = -40 kJ , the standard entropies of X , Y and Z are 60 , 40 and 50JK mol^-1 respectively .The temperature at which the above reaction attains equilibrium is about :

• 400 K

• 500 K

• 273K

• 373K

The dissociation equilibrium of a gas AB₂ can be represented as

$2{\mathrm{AB}}_{2_{\left(\mathrm{g}\right)}} \leftrightharpoons 2 {\mathrm{AB}}_{\left(\mathrm{g}\right)} + {\mathrm{B}}_{2_{\left(\mathrm{g}\right)}}$

The degree of dissociation is x and is small compared to 1. The expression relating the degree of dissociation (x) with equilibrium constant K_P and total pressure p is

• (2K_p/p)^1/2

• K_p/p

• 2K_p/p

• (2kp/p)^1/3

pH of a 0.01 M solution (K_a = 6.6 $\times$ 10^-4)

• 7.6

• 8

• 2.6

• 5

The pH of a 0.02 M solution of HCl is :

• 2.2

• 2.0

• 0.3

• 1.7

The solubility product of Mg(OH)₂ at 25°C is 1.4 x 10^-11 .What is the solubility of Mg(OH)₂ in g/L ?

• 0.0047 g/L

• 0.047 g/L

• 0.0087 g/L

• 0.087 g/L

609.

A vessel of one litre capacity containing 1 mole of SO₃ is heated till a state of equilibrium is attained.

2SO_{3 (g)} $\rightleftharpoons$ 2SO_{2 (g)} + O_{2 (g)}

At equilibrium, 0.6 moles of SO₂ had formed. The value of equilibrium constant is

• 0.18

• 0.36

• 0.45

• 0.68

The equilibrium constant for mutarotation $\mathrm{\alpha }$-D Glucose $\rightleftharpoons$ $\mathrm{\beta }$-D Glucose is 1.8. What percentage of $\mathrm{\alpha }$ form remains at equilibrium?

• 35.7

• 64.3

• 55.6

• 44.4