For a concentrated solution of a weak electrolyte AxBy of concent

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 Multiple Choice QuestionsMultiple Choice Questions

151.

In the reaction H2S+ H2O2 → S+ 2H2O

  • H2S is an acid and H2O2 is a base

  • H2S is a base and H2O2 is an acid

  • H2S is an oxidising agent and H2O2 is a reducing agent

  • H2S is an reducing agent and H2O2 is a oxidising agent


152.

The solubility product (Ks) of the following compounds are given at 25°C
Compounds

Ksp

AgCl 1.1 × 10-10
AgI 1.0 × 10-16
PbCrO4 4.0 × 10-14
Ag2CO3 8.0 × 10-12

The most soluble and least soluble compounds are

  • AgCl and PbCrO4

  • AgI and Ag2CO3

  • AgCl and Ag2CO5

  • Ag2CO3 and AgI


153.

Four moles of PCl5 are heated in a closed 4 dm3 container to reach equilibrium at 400 K. At equilibrium 50% of PCl5 is dissociated. What is the value of Kc for the dissociation of PCl5 into PCl3 and Cl2 at 400 K?

  • 0.50

  • 1.00

  • 1.25

  • 0.05


154.

A weak monobasic acid is 1% ionized in 0.1 M solution at 25°C. The percentage of ionisation in its 0.025 M solution is

  • 1

  • 2

  • 3

  • 4


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155.

The aqueous solution of which of the salt has pH close to 7?

  • FeCl3

  • CH3COONa

  • KCN

  • CH3COONH4


156.

Consider the following reactions in which all the reactants and the products are in gaseous state

  2PQ  P2 + Q2; K1 = 2.5 × 105PQ + 12R2  PQR: K2 = 5 ×10-3The value of K3 for the equilibrium 12P2 +12Q2 +12R2 PQR, is

  • 2.5 × 10-3

  • 2.5 × 103

  • 1.0 × 10-5

  • 5 × 103


157.

At a certain temperature, the dissociation constants of formic acid and acetic acid are 1.8 × 10-4 and 1.8 × 10-5 respectively. The concentration of acetic acid solution in which the hydrogen ion has the same concentration as in 0.001 M formic acid solution is equal to 

  • 0.01 M

  • 0.001 M

  • 0.1 M

  • 0.0001 M


158.

What is the overall formation equilibriumconstant for the ion [ML4]2- ion, given that β4 for this complex is 2.5 × 1013?

  • 2.5 × 1013

  • 5 × 10-13

  • 2.5 × 10-14

  • 4.0 × 10-13


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159.

1.6 moles of PCl5(g) is placed in 4 dm closed vessel. When the temperature is raised to 500 K, it decomposes and at equilibrium 1.2 moles of PCl5(g) remains. What is the K, value for the decomposition of PCl5(g) to PCl3(g) and Cl5(g) at 500 K?

  • 0.013

  • 0.050

  • 0.033

  • 0.067


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160.

For a concentrated solution of a weak electrolyte AxBy of concentration 'C', the degree of dissociation 'a' is given as

  • α = √ Keq/ C ( x + y)

  • α = √ Keq/ C ( xy)

  • α =( Keq/ Cxy)

  • α =( Keq/ Cxy)


A.

α = √ Keq/ C ( x + y)

The weak electrolyte AxBy, dissociates as followsAxBy        xAy+  + yBx-C                     0             0         InItiallyC(1-α)         xCα        yCα    At equilibriumwhere,      α = degreeofdissociation                  C = concentrationKeq = Ay+xBx-y[AxBy]       = xCαx  yCαyC(1-α)  =xx·Cx·αx·yy·Cy·αyC                     [ 1-α 1]=xx·yy·αx+y·Cx+y-1αx+y =Keqxx·yy·Cx+y-1α=Keqxx·yy·Cx+y-11x+y


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