Equilibrium

Which of the following is least likely to behave as Lewis base?

1. H2O
2. NH3
3. BF3
4. OH-

For the reaction, N2(g) + O2(g) 2NO(g), the equilibrium constant is K1. The equilibrium constant is K2 for the reaction, 2NO(g) + O2(g) 2NO2(g) What is K for the reaction, NO2(g) 12N2(g) + O2(g)

1. 12K1K2
2. 14K1K2
3. [ 1K1K2 ]1/2
4. 1K1K2

The reaction, 2A(g) + B(g) 3C(g) + D(g) is begun with the concentrations of A and B both at an initial value of 1.00 M. When equilibrium is reached, the concentration of D is measured and found to be 0.25 M. The value for the equilibrium constant for this reaction is given by the expression

1. [(0.75)3(0.25)] [(1.00)2(1.00)]
2. [(0.75)3(0.25)] [(0.50)2(0.75)]
3. [(0.75)3(0.25)] [(0.50)2(0.25)]
4. [(0.75)3(0.25)] [(0.75)2(0.25)]

If pH of a saturated solution of Ba(OH)2 is 12, the value of its Ksp is

1. 4.00 10-6 M3
2. 4.00 10-7 M3
3. 5.00 10-6 M3
4. 5.00 10-7 M3

What is [H+] in mol/L of a solution that is 0.20 M in CH3COONa and 0.10 M in CH3COOH? Ka for CH3COOH = 1.8 10-5

1. 3.5 10-4
2. 1.1 10-5
3. 1.8 10-5
4. 9.0 10-6

In which of the following equilibrium Kc and Kp are not equal?

1. 2NO(g) N2(g) + O2(g)
2. SO2(g) + NO2(g) SO3(g) + NO(g)
3. H2(g) + I2(g) 2HI(g)
4. 2C(s) + O2(g) 2CO(g)

In a buffer solution containing equal concentration of B- and HB, the Kb for B- is 10-10. The pH of buffer solution is

1. 10
2. 7
3. 6
4. 4

The dissociation constants for acetic acid and HCN at 25 are 1.5 10-5 and 4.5 10-10 respectively. The equilibrium constant for the equilibrium CN- + CH3COOH HCN + CH3COO- would be

1. 3.3 10-5
2. 3.3 10-4
3. 3.3 104
4. 3.3 105

Which of the following molecules acts as a Lewis acid?

1. (CH3)2O
2. (CH3)3P
3. (CH3)3N
4. (CH3)3B

The ionization constant of ammonium hydroxide is 1.77 10-5 at 298 K. Hydrolysis constant of ammonium chloride is

1. 6.50 10-12
2. 5.65 10-13
3. 5.65 10-12
4. 5.65 10-10

What is the [OH-] in the final solution prepared by mixing 20.0 mL of 0.050 M HCl with 30.0 mL of 0.10 M Ba(OH)2?

1. 0.40 M
2. 0.0050 M
3. 0.12 M
4. 0.10 M

The dissociation equilibrium of a gas AB2 can be represented as: 2AB2(g) 2AB(g) + B2(g) The degree of dissociation is x and is small compared to 1. The expression relating the degree of dissociation (x) with equilibrium constant Kp and total pressure P is

1. (2Kp/P)1/2
2. (Kp/P)
3. (2Kp/P)
4. (2Kp/P)1/3

If the concentration of OH- ions in the reaction Fe(OH)3(s) Fe3+(aq) + 3OH-(aq) is decreased by 1/4 times, then equilibrium concentration of Fe3+ will increase by

1. 64 times
2. 4 times
3. 8 times
4. 16 times

Equal volumes of three acid solutions of pH 3, 4 and 5 are mixed in a vessel. What will be the H+ ion concentration in the mixture?

1. 3.7 10-3 M
2. 1.11 10-3 M
3. 1.11 10-4 M
4. 3.7 10-4 M

The value of equilibrium constant of the reaction HI(g) 12H2(g) + 12I2(g) is 8.0. The equilibrium constant of the reaction H2(g) + I2(g) 2HI(g) will be

1. 16
2. 1/8
3. 1/16
4. 1/64

The values of Kp for the reactions, X Y + Z ....(i) A 2B ....(ii) are in the ratio 9 : 1. If degree of dissociation of X and A be equal, then total pressure at equilibrium (i) and (ii) are in the ratio

1. 36 : 1
2. 1 : 1
3. 3 : 1
4. 1 : 9

Equimolar solutions of the following were prepared in water separately. Which one of the solutions will record the highest pH?

1. MgCl2
2. CaCl2
3. SrCl2
4. BaCl2

Which one of the following ionic species has the greatest proton affinity to form stable compound?

1. NH2-
2. F-
3. I-
4. HS-

The equilibrium constants of the following are N2 + 3H2 2NH3; K1 N2 + O2 2NO; K2 H2 + 12O2 H2O; K3 The equilibrium constant (K) of the reaction: 2NH3 + 52O2 2NO + 3H2O will be

1. K2K33/K1
2. K2K3/K1
3. K23K3/K1
4. K1K33/K2

A weak acid, HA, has a Ka of 1.00 10-5. If 0.100 mol of this acid is dissolved in one litre of water, the percentage of acid dissociated at equilibrium is closest to

1. 1.00\%
2. 99.9\%
3. 0.100\%
4. 99.0\%

Calculate the pOH of a solution at 25 C that contains 1 10-10 M of hydronium ions, i.e. H3O+.

1. 4.000
2. 9.000
3. 1.000
4. 7.000

For the reaction : CH4(g) + 2O2(g) CO2(g) + 2H2O(l), Hr = -890.3 kJ mol-1. Which of the following statements is not true?

1. The reaction is exothermic.
2. At equilibrium, the concentrations of CO2(g) and H2O(l) are not equal.
3. The equilibrium constant for the reaction is given by Kp = [CO2][CH4][O2]
4. Addition of CH4(g) or O2(g) at equilibrium will cause a shift to the right.

Which of the following pairs constitutes a buffer?

1. HCl and KCl
2. HNO2 and NaNO2
3. NaOH and NaCl
4. HNO3 and NH4NO3

The hydrogen ion concentration of a 10-8 M, HCl aqueous solution at 298 K (Kw = 10-14) is

1. 1.0 10-8 M
2. 1.0 10-6 M
3. 1.0512 10-7 M
4. 9.512 10-8 M

At 25 , the dissociation constant of a base, BOH, is 1.0 10-12. The concentration of hydroxyl ions in 0.01 M aqueous solution of the base would be

1. 1.0 10-5 mol L-1
2. 1.0 10-6 mol L-1
3. 2.0 10-6 mol L-1
4. 1.0 10-7 mol L-1

H2S gas when passed through a solution of cations containing HCl precipitates the cations of second group of qualitative analysis but not those belonging to the fourth group. It is because

1. presence of HCl decreases the sulphide ion concentration
2. solubility product of group II sulphides is more than that of group IV sulphides
3. presence of HCl increases the sulphide ion concentration
4. sulphides of group IV cations are unstable in HCl.

Equilibrium constants K1 and K2 for the following equilibria: NO(g) + 12O2(g) K1 NO2(g) and 2NO2(g) K2 2NO(g) + O2(g) are related as

1. K2 = 1/K12
2. K2 = K12
3. K2 = 1/K1
4. K2 = K1/2

The solubility product of a sparingly soluble salt AX2 is 3.2 10-11. Its solubility (in moles/L) is

1. 5.6 10-6
2. 3.1 10-4
3. 2 10-4
4. 4 10-4

The rapid change of pH near the stoichiometric point of an acid-base titration is the basis of indicator detection. pH of the solution is related to ratio of the concentrations of the conjugate acid (HIn) and base (In-) forms of the indicator by the expression

1. [In-][HIn] = pKIn - pH
2. [HIn][In-] = pKIn - pH
3. [HIn][In-] = pH - pKIn
4. [In-][HIn] = pH - pKIn

The equilibrium constants of the following are N2 + 3H2 2NH3; K1 N2 + O2 2NO; K2 H2 + 12O2 H2O; K3 The equilibrium constant (K) of the reaction : 2NH3 + 52O2 2NO + 3H2O will be

1. K2K33/K1
2. K2K3/K1
3. K23K3/K1
4. K1K33/K2