Buffer solutions have constant acidity and alkalinity because f

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 Multiple Choice QuestionsMultiple Choice Questions

441.

If the value of an equilibrium constant ofr particular reaction is 1.6 x1012 then at equilibrium the system will contains

  • all reactants

  • mostly reactants

  • mostly products

  • mostly products

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442.

The Ksp of Ag2CrO4, AgCl, AgBr and AgI are respectively, 1.1 x 10-12, 1.8 x 10-11, 8.3 x 10-17. Which one of the following salts will precipitate last if AgNO3 solution is added to the solution containing equal moles of NaCl, NaBr, NaI and Na2CrO4

  • AgI

  • AgCl

  • AgBr

  • AgBr

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443.

Which of the following salts will give highest pH in water?

  • KCl

  • NaCl

  • Na2CO3

  • Na2CO3

1725 Views

444.

For the reversible reaction,

straight N subscript 12 space left parenthesis straight g right parenthesis space plus 3 straight H subscript 2 left parenthesis straight g right parenthesis space rightwards harpoon over leftwards harpoon 2 NH subscript 3 space left parenthesis straight g right parenthesis space plus Heat
the equilibrium shifts in the forward direction

  • by increasing the concentration of NH3 (g)

  • by decreasing the pressure

  • by decreasing the concentrations of N2 (g)  and H2(g)

  • by decreasing the concentrations of N2 (g)  and H2(g)

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445.

For a given exothermic reaction Kp and Kp' are the equilibrium constant at temperatures T1 and T2 respectively. Assuming that heat of reaction si constant in temperature range between T1 and T2 it is readily observed that

  • Kp> Kp'

  • Kp< Kp'

  • Kp = Kp'

  • Kp = Kp'

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446.

Which of these is least likely to act as a lewis base? 

  • CO

  • F-

  • BF3

  • BF3

2159 Views

447.

pH of a saturated solution of Ba(OH)2 is 12. The value of solubility product Ksp of Ba(OH)2 is

  • 3.3 x 10-7

  • 5.0 x 10-7

  • 4.0 x 10-6

  • 4.0 x 10-6

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448.

Equimolar solutions of the following substances were prepared separately, which one of these will record the highest pH value?

  • BaCl2

  • AlCl3

  • LiCl

  • LiCl

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449.

Buffer solutions have constant acidity and alkalinity because

  • these give unionised acid or base on reaction with added acid or alkali

  • acids and alkalies in these solutions are shielded from attack by other ions.

  • they have a large excess of H+ or OH- ions

  • they have a large excess of H+ or OH- ions


A.

these give unionised acid or base on reaction with added acid or alkali

If a small amount of an acid or alkali is added to a buffer solution, it converts them into unionised acid or base. Thus, remains unaffected or in other words its acidity/alkalinity remains constant. e.g.,

H3O+ + A-  ⇌ H2O +HA

-OH +HA → H2O +A-
If acid is added, it reacts with A- to form undissociated HA. Similarly, if base/alkali is added, O H- combines with HA to give H2O and A- and thus, maintains the acidity/alkalinity of buffer solution.

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450.

Give that the equilibrium constant for the reaction,

2SO2 (g) + O2 (g)  ⇌ 2SO3 (g)

has a value of 278 at a particular temperature. What is the value of the equilibrium constant for the following reaction t the same temperature?

SO3 (g)  ⇌ SO2 (g) +1/2 O2 (g)

  • 1.8 x 10-3

  • 3.6 x 10-3

  • 6.0 x 10-2

  • 6.0 x 10-2

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