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What are simple buffers?

Important Questions on Equilibria

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Chemistry>Physical Chemistry>Equilibria>Buffer Solutions

A buffer solution can be prepared by mixing equal volumes of

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Chemistry>Physical Chemistry>Equilibria>Buffer Solutions

If the

pH

of a solution containing

10 mL

0.5 M {CH}_{3} COOH

and

10 mL

0.25 M NaOH

5

. What is the

{pK}_{a}

of the acid?

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Chemistry>Physical Chemistry>Equilibria>Buffer Solutions

Among the following, the correct statement is

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Chemistry>Physical Chemistry>Equilibria>Buffer Solutions

In order to prepare a buffer solution of

pH 5.74

, sodium acetate is added to acetic acid. If the concentration of acetic acid in the buffer is

1.0 M,

the concentration of sodium acetate in the buffer is ______

M .

(Round off to the Nearest Integer).

[Given : pKa (acetic acid) = 4.74]

HARD

Chemistry>Physical Chemistry>Equilibria>Buffer Solutions

When 100 mL of 1.0 M HCl was mixed with 100 mL of 1.0 M NaOH in an insulated beaker at constant pressure, a temperature increase of

{5.7}^{o} C

was measured for the beaker and its contents (Expt.1). Because the enthalpy of neutralization of a strong acid with a strong base is a constant

(- 57.0 k J m o l^{- 1})

, this experiment could be used to measure the calorimeter constant. In a second experiment (Expt. 2), 100 mL of 2.0 M acetic acid

(K_{a} = 2.0 \times 10^{- 5})

was mixed with 100 mL of 1.0 M NaOH (under identical conditions to Expt. 1) where a temperature rise of

{5.6}^{o} C

was measured. (Consider heat capacity of all solutions as

4.2 J g^{- 1} K^{- 1}

and density of all solutions as

1.0 g m L^{- 1}

)

The pH of the solution after Expt. 2 is

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What will be the

pH

of solution formed by mixing

10 mL 0.1 {MNaH}_{2} {PO}_{4}

15 mL

0.1 {MNa}_{2} {HPO}_{4}

[Given:

{pK}_{1} = 2.12, {pK}_{2} = 7.2]

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Chemistry>Physical Chemistry>Equilibria>Buffer Solutions

Which of the following mixtures will have the lowest pH at $298 K ?$

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Chemistry>Physical Chemistry>Equilibria>Buffer Solutions

For a buffer of a mixture of

0.12 mol L^{- 1}

{CH}_{3} COOH

and

0.12 mol L^{- 1} {CH}_{3} COONa,

the buffer capacity is

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Chemistry>Physical Chemistry>Equilibria>Buffer Solutions

Which will make basic buffer?

HARD

Chemistry>Physical Chemistry>Equilibria>Buffer Solutions

A solution of $0.1 M$ weak base $(B)$ is titrated with $0.1 M$ of a strong acid $(HA)$ . The variation of $pH$ of the solution with the volume of $HA$ added is shown in the figure below. What is the ${pK}_{b}$ of the base? The neutralisation reaction is given by $B + HA \to {BH}^{+} + A^{-}$ .

Question Image

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Chemistry>Physical Chemistry>Equilibria>Buffer Solutions

20 ml

{0.1 M H}_{2} {SO}_{4}

solution is added to

30 mL

0 .2 M {NH}_{4} OH

solution. The

pH

of the resultant mixture is:

[{pk}_{b} of {NH}_{4} OH = 4 .7]

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Chemistry>Physical Chemistry>Equilibria>Buffer Solutions

Addition of sodium hydroxide solution to a weak acid (HA) results in a buffer of pH 6. If ionization constant of HA is

10^{- 5}

, the ratio of salt to acid concentration in the buffer solution will be:

HARD

Chemistry>Physical Chemistry>Equilibria>Buffer Solutions

A solution of

0.1

mole of

{CH}_{3} {NH}_{2} (K_{b} = 5 \times 10^{- 4})

and

0.08 mole

HCl

is diluted to one litre, then the

pOH

of the solution is

(\log 1.25 = 0.1)

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Chemistry>Physical Chemistry>Equilibria>Buffer Solutions

50 mL

0 .2 M

ammonia solution is treated with

25 mL of 0.2 M HCl

. If

{pK}_{b}

of ammonia solution is

4.75

, the

pH

of the mixture will be:

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Chemistry>Physical Chemistry>Equilibria>Buffer Solutions

Which one of the following pairs of solution is not an acidic buffer?

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Chemistry>Physical Chemistry>Equilibria>Buffer Solutions

Which of the following pairs constitutes a buffer?

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Chemistry>Physical Chemistry>Equilibria>Buffer Solutions

Aqueous solution of borax acts as a buffer because :

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Chemistry>Physical Chemistry>Equilibria>Buffer Solutions

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 the ratio of the concentrations of the conjugate acid

HIn

and base

{In}^{-}

. The expression that relates these terms is

HARD

Chemistry>Physical Chemistry>Equilibria>Buffer Solutions

If one was to prepare a buffer solution using pyridine

(C_{5} H_{5} N, K_{b} = 1.8 \times 10^{- 9} M)

and pyridinium chloride

(C_{5} H_{5} NCl)

, its

pH

would be between

HARD

Chemistry>Physical Chemistry>Equilibria>Buffer Solutions

For the indicator the ratio

\frac{[{In}^{-}]}{[HIn]}

is 7.0 at pH of 4.3. K_eq for the indicator is

[Given log 7 = 0.845 and Anti log (0.455) = 3.5]

What are simple buffers?

Important Questions on Equilibria

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