﻿ IIT - JEE Main Important Questions of Equilibrium | Zigya

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# Equilibrium

#### Multiple Choice Questions

1.

For the reaction,

if Kp = Kc (RT)x where the symbol has usual meaning then the value of x is (assuming ideality)

• -1

• -1/2

• 1/2

• 1

B.

-1/2

For  the given reaction, ∆ng = np-nR
where np = number of moles of products
nR = number of moles of reactants
Kp = Kc (RT)∆ng

∆ng = -1/2

391 Views

2.

In aqueous solution the ionization constants for carbonic acid are
K1 = 4.2 x 10-7 and K2 = 4.8 x 10-11.
Select the correct statement for a saturated 0.034 M solution of the carbonic acid.

• The concentration of CO32- is 0.034 M

• The concentration of CO32- is greater than that of HCO3-

• The concentration of H+ and HCO3- are approximately equal

• The concentration of H+ is double that of CO32-

C.

The concentration of H+ and HCO3- are approximately equal

Second dissociation constant is much smaller than the first one. Just a small fraction of total HCO3- formed will undergo the second stage of ionization. Hence in a saturated solution.
451 Views

3.

The correct order of increasing basicity of the given conjugate bases (R = CH3) is

A.

Stronger acid has a weaker conjugate base.
Order of acidity : RCOOH > CH≡CH > NH3 > RH

Order of basicity :

423 Views

4.

Three reactions involving H2PO4- are given below
I. H3PO4 + H2O → H3O+ + H2PO4-
II. H2PO4- + H2O→ HPO42- + H3O+
III. H2PO4- + OH- → H3PO4  + O2-
In which of the above does H2PO4- act  as an acid

• (II) only

• (I) and (II)

• (III) only

• (I) only

A.

(II) only

389 Views

5.

At 25°C, the solubility product of Mg(OH)2 is 1.0 × 10–11. At which pH, will Mg2+ ions start precipitating in the form of Mg(OH)2 from a solution of 0.001 M Mg2+ ions?

• 9

• 10

• 11

• 8

B.

10

342 Views

6.

Consider the reaction:
Cl2(aq) + H2S(aq) → S (s) + 2H+ (aq) + 2Cl- (aq)
The rate equation for this reaction is
I. Cl2 + H2S → H+ +Cl- + Cl+ +HS-
II. H2S ⇌ H+ + HS- (fast equilibrium)
Cl2 + HS- → 2Cl- + H+ + S (slow)

• II only

• Both (I) and (II)

• Neither (I) nor (II)

• (I) only

D.

(I) only

For (A)
rate = K[Cl2] [H2S]
For (B)
rate = K[Cl2] [HS-] … (i)

336 Views

7.

The pH of a 0.1 molar solution of the acid HQ is 3. The value of the ionisation constant, Ka of this acid is

• 3 x 10–1

• 1 x 10–3

• 1 x 10—5

• 1 x 10–7

C.

1 x 10—5

HQ = H+ + Q-

705 Views

8.

The species which can best serve as an initiator for the cationic polymerization is

• LiAlH4

• HNO3

• AlCl3

• BaLi

C.

AlCl3

Electron-deficient species (Lewis acid) like AlCl3, BF3, etc, are is used as an initiator for cationic polymerisation.

343 Views

9.

The equilibrium constant (Kc) for the reaction, N2(g) + O2 (g) → 2NO (g) at temperature T is 4 x 10-4. The value of Kc for the reaction  at the same temperature is

• 0.02

• 2.5 x 102

• 4 x 10-4

• 50.0

D.

50.0

1948 Views

10.

The equilibrium constant at 298 K for a reaction A+B ⇌ C+D is 100. If the initial concentration of all the four species were 1 M each, then equilibrium concentration of D (in mol L−1 ) will be:

• 0.818

• 1.818

• 1.182

• 0.182

B.

1.818

545 Views