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Equilibrium · Question 60

AIPMT 2011 (Prelims)MCQMedium📈 Topic in 25% papers+4−1
1

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

Answer

(2) 9.43

Solution

For a basic buffer: [OH-] = Kb [NH3][NH4+]

= 1.8 10-5 0.300.20

= 2.7 10-5 M

pOH = - (2.7 10-5)

= 5 - 0.43 = 4.57

pH = 14 - 4.57 = 9.43

Answer: (2)

AIPMT 2011 (Prelims)

Keep practising — Equilibrium

2

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

  1. H2O
  2. NH3
  3. BF3
  4. OH-
AIPMT 2011 (Prelims)
3

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
AIPMT 2011 (Prelims)
4

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)]
AIPMT 2010 (Mains)
5

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
AIPMT 2010 (Prelims)
6

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
AIPMT 2010 (Prelims)
7

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)
AIPMT 2010 (Prelims)
8

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
AIPMT 2010 (Prelims)
9

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
AIPMT 2009
10

Which of the following molecules acts as a Lewis acid?

  1. (CH3)2O
  2. (CH3)3P
  3. (CH3)3N
  4. (CH3)3B
AIPMT 2009
11

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
AIPMT 2009

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