Equilibrium

Concentration of the Ag+ ions in a saturated solution of Ag2C2O4 is 2.2 10-4 mol L-1. Solubility product of Ag2C2O4 is

1. 2.66 10-12
2. 4.5 10-11
3. 5.3 10-12
4. 2.42 10-8

A 20 litre container at 400 K contains CO2(g) at pressure 0.4 atm and an excess of SrO (neglect the volume of solid SrO). The volume of the container is now decreased by moving the movable piston fitted in the container. The maximum volume of the container, when pressure of CO2 attains its maximum value, will be (Given that : SrCO3(s) SrO(s) + CO2(g), Kp = 1.6 atm)

1. 10 litre
2. 4 litre
3. 2 litre
4. 5 litre

Consider the following liquid-vapour equilibrium. Liquid Vapour Which of the following relations is correct ?

1. d PdT2 = - HvT2
2. d PdT = HvRT2
3. d GdT2 = HvRT2
4. d PdT = - HvRT

MY and NY3, two nearly insoluble salts, have the same Ksp values of 6.2 10-13 at room temperature. Which statement would be true in regard to MY and NY3?

1. The salts MY and NY3 are more soluble in 0.5 M KY than in pure water.
2. The addition of the salt of KY to solution of MY and NY3 will have no effect on their solubilities.
3. The molar solubilities of MY and NY3 in water are identical.
4. The molar solubility of MY in water is less than that of NY3.

The percentage of pyridine (C5H5N) that forms pyridinium ion (C5H5N+H) in a 0.10 M aqueous pyridine solution (Kb for C5H5N = 1.7 10-9) is

1. 0.0060%
2. 0.013%
3. 0.77%
4. 1.6%

The solubility of AgCl(s) with solubility product 1.6 10-10 in 0.1 M NaCl solution would be

1. 1.25 10-5 M
2. 1.6 10-9 M
3. 1.6 10-11 M
4. zero

Which of the following fluoro-compounds is most likely to behave as a Lewis base ?

1. BF3
2. PF3
3. CF4
4. SiF4

If the equilibrium constant for N2(g) + O2(g) 2NO(g) is K, the equilibrium constant for 12 N2(g) + 12 O2(g) NO(g) will be

1. 12K
2. K
3. K2
4. K1/2

What is the pH of the resulting solution when equal volumes of 0.1 M NaOH and 0.01 M HCl are mixed?

1. 2.0
2. 7.0
3. 1.04
4. 12.65

Which one of the following pairs of solution is not an acidic buffer ?

1. CH3COOH and CH3COONa
2. H2CO3 and Na2CO3
3. H3PO4 and Na3PO4
4. HClO4 and NaClO4

The Ksp of Ag2CrO4, AgCl, AgBr and AgI are respectively, 1.1 10-12, 1.8 10-10, 5.0 10-13, 8.3 10-17. Which one of the following salts will precipitate last if AgNO3 solution is added to the solution containing equal moles of NaCl, NaBr, NaI and Na2CrO4?

1. AgBr
2. Ag2CrO4
3. AgI
4. AgCl

If the value of equilibrium constant for a particular reaction is 1.6 1012, then at equilibrium the system will contain

1. mostly products
2. similar amounts of reactants and products
3. all reactants
4. mostly reactants.

Which of the following salts will give highest pH in water?

1. KCl
2. NaCl
3. Na2CO3
4. CuSO4

Using the Gibbs energy change, G = +63.3 kJ, for the following reaction, Ag2CO3(s) 2Ag+(aq) + CO32-(aq) the Ksp of Ag2CO3(s) in water at 25 C is ( R = 8.314 J K-1 mol-1)

1. 3.2 10-26
2. 8.0 10-12
3. 2.9 10-3
4. 7.9 10-2

For the reversible reaction, N2(g) + 3H2(g) 2NH3(g) + heat The equilibrium shifts in forward direction

1. by increasing the concentration of NH3(g)
2. by decreasing the pressure
3. by decreasing the concentrations of N2(g) and H2(g)
4. by increasing pressure and decreasing temperature.

For a given exothermic reaction, Kp and K'p are the equilibrium constants at temperatures T1 and T2, respectively. Assuming that heat of reaction is constant in temperature range between T1 and T2, it is readily observed that

1. Kp > K'p
2. Kp < K'p
3. Kp = K'p
4. Kp = 1K'p

Which of these is least likely to act as a Lewis base ?

1. BF3
2. PF3
3. CO
4. F-

Identify the correct order of solubility in aqueous medium.

1. Na2S > CuS > ZnS
2. Na2S > ZnS > CuS
3. CuS > ZnS > Na2S
4. ZnS > Na2S > CuS

Accumulation of lactic acid (HC3H5O3), a monobasic acid in tissues leads to pain and a feeling of fatigue. In a 0.10 M aqueous solution, lactic acid is 3.7% dissociated. The value of dissociation constant, Ka, for this acid will be

1. 1.4 10-5
2. 1.4 10-4
3. 3.7 10-4
4. 2.8 10-4

At 100 the Kw of water is 55 times its value at 25 . What will be the pH of neutral solution? (log 55 = 1.74)

1. 7.00
2. 7.87
3. 5.13
4. 6.13

The values of Ksp of CaCO3 and CaC2O4 are 4.7 10-9 and 1.3 10-9 respectively at 25 . If the mixture of these two is washed with water, what is the concentration of Ca2+ ions in water ?

1. 5.831 10-5 M
2. 6.856 10-5 M
3. 3.606 10-5 M
4. 7.746 10-5 M

The dissociation constant of weak acid is 1 10-4. In order to prepare a buffer solution with a pH = 5, the [Salt]/[Acid] ratio should be

1. 4 : 5
2. 10 : 1
3. 5 : 4
4. 1 : 10

Given that the equilibrium constant for the reaction, 2SO2(g) + O2(g) 2SO3(g) has a value of 278 at a particular temperature. What is the value of the equilibrium constant for the following reaction at the same temperature ? SO3(g) SO2(g) + 12O2(g)

1. 1.8 10-3
2. 3.6 10-3
3. 6.0 10-2
4. 1.3 10-5

Given the reaction between 2 gases represented by A2 and B2 to give the compound AB(g), A2(g) + B2(g) 2AB(g) At equilibrium, the concentration of A2 = 3.0 10-3 M, of B2 = 4.2 10-3 M, of AB = 2.8 10-3 M If the reaction takes place in a sealed vessel at 527 , then the value of Kc will be

1. 2.0
2. 1.9
3. 0.62
4. 4.5

pH of a saturated solution of Ba(OH)2 is 12. The value of solubility product (Ksp) of Ba(OH)2 is

1. 3.3 10-7
2. 5.0 10-7
3. 4.0 10-6
4. 5.0 10-6

Equimolar solutions of the following substances were prepared separately. Which one of these will record the highest pH value ?

1. BaCl2
2. AlCl3
3. LiCl
4. BeCl2

Buffer solutions have constant acidity and alkalinity because

1. these give unionised acid or base on reaction with added acid or alkali
2. acids and alkalies in these solutions are shielded from attack by other ions
3. they have large excess of H+ or OH- ions
4. they have fixed value of pH

In qualitative analysis, the metals of group I can be separated from other ions by precipitating them as chloride salts. A solution initially contains Ag+ and Pb2+ at a concentration of 0.10 M. Aqueous HCl is added to this solution until the Cl- concentration is 0.10 M. What will the concentrations of Ag+ and Pb2+ be at equilibrium ? ( Ksp for AgCl = 1.8 10-10, Ksp for PbCl2 = 1.7 10-5)

1. [Ag+] = 1.8 10-7 M, [ Pb2+] = 1.7 10-6 M
2. [Ag+] = 1.8 10-11 M, [ Pb2+] = 8.5 10-5 M
3. [Ag+] = 1.8 10-9 M, [ Pb2+] = 1.7 10-3 M
4. [Ag+] = 1.8 10-11 M, [ Pb2+] = 1.7 10-4 M

The value of H for the reaction X2(g) + 4Y2(g) 2XY4(g) is less than zero. Formation of XY4(g) will be favoured at

1. high temperature and high pressure
2. low pressure and low temperature
3. high temperature and low pressure
4. high pressure and low temperature

A buffer solution is prepared in which the concentration of NH3 is 0.30 M and the concentration of NH4+ is 0.20 M. If the equilibrium constant, Kb for NH3 equals 1.8 10-5, what is the pH of this solution? ( 2.7 = 0.43)

1. 9.08
2. 9.43
3. 11.72
4. 8.73