Two moles of PCl5 were heated in a closed vessel of 2 L. At equil

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 Multiple Choice QuestionsMultiple Choice Questions

351.

The pair of compound which cannot exist together in solution is

  • NaHCO3 and NaOH

  • NaHCO3 and H2O

  • NaHCO3 and Na2CO3

  • Na2COand NaOH


352.

Which is most basic in character ?

  • CsOH

  • KOH

  • NaOH

  • LiOH


353.

Would gaseous HCl be considered as an Arrhenius acid ?

  • Yes

  • No

  • Not known

  • Gaseous HCl does not exist


354.

The degree of hydrolysis in hydrolytic equilibrium

A- + H2 HZ + OH-

at salt concentration of 0.001 M is :

(Ka = 1 × 10-5)

  • 1 × 10-3

  • 1 × 10-4

  • 5 × 10-4

  • 1 × 10-6


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355.

The reaction quotient 'Q' is useful in predicting the direction of the reaction. Which of the following is incorrect?

  • If Qc < Kc, the forward reaction is favoured

  • If Qc > Kc, the forward reaction is favoured

  • If Qc >Kc, the forward reaction is favoured and Qc =Kc, no reaction occur.

  • None of these


356.

pH of 1M NH3 aqueous solution is (Kb = 1.8 × 10-5)

  • 11.13

  • 12.5

  • 13.42

  • 11.55


357.

Equivalent weight of an acid :

  • depends on the reaction involved

  • depends upon the number of oxygen atoms present

  • is always constant

  • None of the above


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358.

Two moles of PCl5 were heated in a closed vessel of 2 L. At equilibrium, 40% of PCl5 is dissociated into PCl3 and Cl3. The value of equilibrium constant is :

  • 0.53

  • 0.267

  • 2.63

  • 5.3


B.

0.267

Given, 

Initial concentration of PCl5 = a = 2 moles

Degree of dissociation = x = 0.4 (40%)

Volume = V = 2L

Initial concentrationAt equilibrium PCl5aa (1 - x)  PCl30ax + Cl20ax According to law of mass actionKc = [PCl3][Cl2][PCl5]    = ax × axa(1 - x)    = (2 × 0.4 / 2)22(1 - 0.4)    = (0.4)20.6     = 0.4 × 0.40.6 = 0.267


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359.

The solubility product of Barium sulphate is 1.5 × 10-9 at 18°C. Its solubility in water at 18°C is :

  • 1.5 × 10-9

  • 1.5 × 10-5

  • 3.9 × 10-9

  • 3.9 × 10-5


360.

pH scale was introduced by :

  • Arrhenius

  • Sorensen

  • Lewis

  • Lowry


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