CHEMISTRY-Chemical Equilibrium (SMART INSTITUTE)

01-In the reaction A_2(g) + 4B_2(g)⇌ 2AB_4(g) such that ΔH < 0, the formation of AB₄ will be favoured at:

Low temperature and high pressure

High temperature and low pressure

Low temperature and low pressure

High temperature and high pressure

02-Consider the reaction PCl_{5 (g)} ⇌ PCl_{3 (g)} +Cl_{2 (g)} in a closed container at equilibrium. At a fixed temperature, what will be the effect of adding more PCl5 on the equilibrium constant:

It increases

It remains unaffected

It decreases

Can't be predicted without K P

03-The oxidation of SO₂ to SO₃ is exothermic reaction. The yield of SO3 will be maximum if:

Temperature is increased and pressure is kept constant

Temperature is reduced and pressure is increased

Both temperature and pressure are increased

Both temperature and pressure are decreased

04-If the concentration of salt is greater than the acid in buffer solution, then the

PH=pKa

PH=pKb

PH>pKa

05-In a saturated solution of AgCl, the molar concentration of Ag+ and Cl- is 1.0 x 10^-5

mol dm^-3 of each. What is the value of Ksp?

1.0 x 10^-5

0.1 x 10^-5

1.0 x 10^-15

1.0 x 10^-10

06-The solubility of Fe(OH)₃ is 'x' mole per dm3. Its Ksp would be

9x^3

27x^4

3x^4

9x^4

07-For the reaction H_{2 (g)} + I_{2 (g)} ⇌ 2HI _(g). The equilibrium constant changes with

Total pressure

Concentration of H2 and I2

Catalyst

Temperature

08-The decomposition of N₂O₄ to NO₂ is carried out at 280 'C in Chloroform. When equilibrium is reached, 0.2 moles of N₂O₄ and 0.02 mole of NO₂ are present in 1 : 1 ratio. The equilibrium constant for the reaction N₂O₄ → 2NO₂ is:

0.01

0.001

0.02

0.002

09-In a given system, water and ice are in equilibrium, if the pressure is applied to the above system then

More ice is formed

Amount of ice and water will remain the same

More ice is melted

First two options

10-The solubility product of AgCl is 2.0 x 10^-10 mol²dm^-6. The maximum concentration of Ag+ ions in the solution is:

1.41 x 10-5 mol dm-3

1.41 x 10-10 mol dm-3

2.0 x 10-10 mol dm-3

4.0 x 10-20 mol dm-3

11-An excess of silver nitrate is added to the aqueous Barium Chloride and the precipitate is removed by filtration. What are the main ions in the filtrate

Ag+ and NO-3 only

NO-3 and Ba+2 only

Ag+ , NO-3 and Ba+2 only

Cl- , NO-3 and Ba+2 only

13-The most suitable temperature for preparing ammonia gas is:

250 'C

450 'C

350 'C

550 'C

14-The Kw of water at 25 'C is given by

10^-7

10^-10

10-^12

10^14

15-When HCl gas is passed through saturated solution of rock salt, the solubility of NaCl

Increases

May increase or decrease

Decreases

None of above

16-For what value of Kc almost forward reaction is complete

Kc=10^-30

Kc=1

Kc=10^30

Kc=0

17-In which of the following Equilibria will Kc and Kp have not the same value

2HI ⇌ H2 + I2

2SO2 + O2 ⇌ 2SO3

N2+O2 ⇌ 2NO

All of these

18-Correct relationship b/w Kc and Kp can be written as

Kp=Kc(R)^Δn

Kc=Kp (RT)^Δn

Kp=Kc(RT)^Δn

Kp=Kc(R/N)^Δn

19-If the temperature is increased of following reaction, then it will go in

N₂ + 3H₂ ⇌ 2NH₃ ΔH=-VE

Forward direction

Remain constant

Reverse direction

Cannot be predicted

20-If the volume term is present in denominator of Kc expression, then which one is correct?

Increase in pressure will shift the reaction backward

Increase in pressure willshift the reaction forward direction

Decrease in volume will shift the reaction forward direction

Reaction will not be affected

21-Which statement is incorrect?

PH and [OH-] are inversely related to each other

POH and [OH-] are inversely related to each other

PH and [OH-] are directly related to each other

POH means potential pf hydroxyl ion concentration

22. pH of an aqueous solution is 3.0 at 25 'C. The hydrogen ion concentration in the solution would be

0.001

0.01

0.0001

10^-5

24-Which one is correct about conjugate acid-base concept?

A) conjugate base of a very weak acid is relatively very strong

B) conjugate base of a very weak acid is relatively very weak

C) conjugate base of a very strong acid is relatively very weak

Both a and c

25-Which one increases by common ion effect except?

Crystallization

Solubility

Association of ions

All of these

26-A basic buffer solution can be prepared by mixing

Strong acid and its salt with weak base

Strong base and its salt with weak acid

Weak base and its salt with strong acid

Weak acid and its salt with strong base

27-Which one is best buffer those have

PH=pKa

PH>pKa

POH

PKa=0

29-If ionic product is equal to Ksp the the solution is

Unsaturated

Ideal

Supersaturated

Saturated

30-The solubility product is only applicable for those substance whose molar concentration is

0.01

Equal to 1

Less than 0.01

Greater than 10

31-What will be the pH of 1.0 mol dm-3 of H2X, which is only 50% disassociated

Less than 0

32-What will be pH of 1.0 mol dm-3 of NH4OH, which is 1 % disassociated

2.7

33-Buffer solutions are used in except:

Clinical analysis

Nutrition

Soil sciences

Qualitative analysis

34-Buffer action can be explained by except:

Common ion effect

Le-Chatlier's Principle

Law of mass action

Solubility product

35-At equilibrium, the concentration of reactants and products are

Constant

Maximum

Different

Equal

36-For N₂ + 3H₂ ⇌ 2NH₃, if Kc is 1 than value of Kp at 273K would be:

1/22.414

1/(22.414)^2

22.414

11.207

37-Which is correct relating at 100 'C

PH + pOH < 14

[H+] [OH-] >10^-14

PKa + pKb < 14

All of these

38-Expression of solubility product constant (Ksp) for following sparingly soluble salt is

AxBy ⇌ xA^+y + yB^-x

[A^+y]^x [B^-x]^y

[A^y]^y [B^-x]^x

[A^-y]^x [B^-x]^y

[x^A]^y [y^-B]^x

39-Basic buffer solution is

HF/NaF

(COOH)2 / (COONa)2

H2CO3 / Na2CO3

NH4OH / NH4Cl

40-In Haber process, equilibrium mixture contains ........... NH3 by volume.

20 %

55 %

70 %

35 %

41-The value of Kc for H2O at 25 'C is:

1 x 10^-14 mol dm-3

14 mol dm-3

1.86 x 10^-16 mol dm-3

1.0 x 10^-7 mol dm-3

42-Ionization of KClO3 is suppressed by

Increasing temperature

Adding KCl

Adding NaNO3

Decreasing temperature

43. 4 moles of A are mixed with 4 moles of B. At equilibrium for the reaction A + B ⇌

C + D, 2 moles of C and D are formed, the equilibrium constant reaction will be:

1/4

1/2

44-Select the pKa values of strongest acid from following

2.0

3.0

4.5

45-WOF is not favourable for SO3 formation;

2SO_{3 (g) +} O_{2 (g)} ⇌ 2SO_{3 (g)} , ΔH=-45 kcal

High pressure

High temperature

Decreasing SO3 concentration

Increasing reactant concentration

46-The reaction quotient (Q) for the reaction N_{2 (g)} +3H₂ ⇌ 2NH_{3 (g)} is given by Q= [NH3]^2 / [N2] [H2]^3 , the reaction will proceed from right to left is

Q=0

Q=Kc

Q>Kc

47-According to the Lowery Bronsted concept, correct order of relative strength of bases follows the order

Cl- > CH3COO- > OH-

OH- > CH3COO- > Cl-

Cl- > OH-> CH3COO-

OH- > Cl- > CH3COO-

48-Which value of Kc indicates maximum yield of products

Kc=10^2

Kc=10^-2

Kc=1

Kc=10^-3

49-The pH of 1 M MOH solution is only 10% disassociated

50-Addition of catalyst to a chemical reaction will bring about a change in which of the following characteristics of reaction

I.activation energy

II.Enthalpy change

III.value of equilibrium constant

I only

I and II

II only

I and III

51-The rate constant for forward and backward reaction of hydrolysis of ester are 1 x 10^-2 and 2 x 10^-3 respectively. The Kc of reaction is:

52. 1 mole of Ethyl Alcohol was treated with one mole of Acetic Acid at 25 'C. 2/3rd of acid changes into ester at equilibrium. The equilibrium constant of the reaction will be

53-The equilibrium expression for a reaction is Kc=X² / V(a-X), what is true for this reaction.

Increase of pressure favoured forward reaction

Decrease of pressure favoured forward reaction

Decrease oof pressure favoured backward reaction

Increase in volume favoured backward reaction

54-WOF depends upon temperature

Kw + Kc

Ka + Kb

Ksp

All of these

55-If pKa of an acid is 5, then pKb of its conjugate base will be ..... at 25 'C.

56-For the following gases equilibrium, N₂O_4(g) ⇌ 2NO_{2 (g)} at STP. Kp should be equal to

2Kc

22.414 Kc

0.0821 Kc

57-The value of Kw in an acidic aqueous solution at 298 K is

> 10^-14

<10^-14

10^14

10^-14

58-For acidic buffer, pH < pKa if

[salt] = [acid]

[salt] < [acid]

[salt] > [acid]

[salt] > [base]

59-Which is correct statement

PKa x pKb =14

PKa + pKb = Kw

Ka x Kb = pKw

Ka x Kb = Kw

60-For reaction PCl_5(g) ⇌ PCl_3(g) + Cl_2(g) unit of Kp is

Atm

Atm-2

Atm-1

Atm2

CHEMISTRY-Chemical Equilibrium (SMART INSTITUTE)

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