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Equilibrium · Question 82

AIPMT 2006MCQMedium📈 Topic in 25% papers+4−1
1

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.

Answer

(3) The equilibrium constant for the reaction is given by Kp = [CO2][CH4][O2]

Solution

(1) Hr is negative ⇒ the reaction is exothermic ⇒ true.

(2) H2O(l) is a pure liquid; its concentration is constant and is not equal to that of CO2(g) ⇒ true.

(3) Kp is written in terms of partial pressures, each raised to its stoichiometric coefficient, and the pure liquid water is omitted:

Kp = pCO2pCH4 pO22

The given expression uses concentrations and omits the power 2 on O2 ⇒ not true.

(4) By Le Chatelier's principle, adding a reactant shifts the equilibrium to the right ⇒ true.

Answer: (3)

AIPMT 2006

Keep practising — Equilibrium

2

Which of the following pairs constitutes a buffer?

  1. HCl and KCl
  2. HNO2 and NaNO2
  3. NaOH and NaCl
  4. HNO3 and NH4NO3
AIPMT 2006
3

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
AIPMT 2006
4

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
AIPMT 2005
5

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.
AIPMT 2005
6

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
AIPMT 2005
7

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
AIPMT 2004
8

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
AIPMT 2004
9

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
AIPMT 2003
10

The reaction quotient (Q) for the reaction N2(g) + 3H2(g) 2NH3(g) is given by Q = [NH3]2[N2][H2]3. The reaction will proceed from right to left if

  1. Q = Kc
  2. Q < Kc
  3. Q > Kc
  4. Q = 0
AIPMT 2003
11

The solubility product of AgI at 25 C is 1.0 10-16 mol2 L-2. The solubility of AgI in 10-4 N solution of KI at 25 C is approximately (in mol L-1)

  1. 1.0 10-16
  2. 1.0 10-12
  3. 1.0 10-10
  4. 1.0 10-8
AIPMT 2003

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