EASY

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Define buffer solution. What is it mainly used for?

Important Questions on Further Aspects of Equilibria

MEDIUM

Chemistry>Physical Chemistry>Further Aspects of Equilibria>Buffer Solution

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

HARD

Chemistry>Physical Chemistry>Further Aspects of Equilibria>Buffer Solution

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 $B + HA \to {BH}^{+} + A^{-}$ .

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MEDIUM

Chemistry>Physical Chemistry>Further Aspects of Equilibria>Buffer Solution

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?

MEDIUM

Chemistry>Physical Chemistry>Further Aspects of Equilibria>Buffer Solution

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]

HARD

Chemistry>Physical Chemistry>Further Aspects of Equilibria>Buffer Solution

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

HARD

Chemistry>Physical Chemistry>Further Aspects of Equilibria>Buffer Solution

A buffer solution can be prepared by mixing equal volumes of

HARD

Chemistry>Physical Chemistry>Further Aspects of Equilibria>Buffer Solution

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)

MEDIUM

Chemistry>Physical Chemistry>Further Aspects of Equilibria>Buffer Solution

The

{OH}^{-}

concentration in a mixture of

5.0 mL

0.0504 M {NH}_{4} Cl

and

2 mL

0.0210 M {NH}_{3}

solution is

x \times 10^{- 6} M

. The value of

x

is (Nearest integer) [Given

K_{w} = 1 \times 10^{- 14}

and

K_{b} = 1.8 \times 10^{- 5}]

MEDIUM

Chemistry>Physical Chemistry>Further Aspects of Equilibria>Buffer Solution

Which will make basic buffer?

HARD

Chemistry>Physical Chemistry>Further Aspects of Equilibria>Buffer Solution

3 g

of acetic acid is added to

250 m L

0.1 M H C l

and the solution made up to

500 m L

. To

20 m L

of this solution

\frac{1}{2} m L

5 M N a O H

is added. The

p H

of the solution is ________
[Given:

p K a

of acetic acid

= 4.75,

molar mass of acetic acid

60 g / m o l, \log 3 = 0.4771

, Neglect any changes in volume]

EASY

Chemistry>Physical Chemistry>Further Aspects of Equilibria>Buffer Solution

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

EASY

Chemistry>Physical Chemistry>Further Aspects of Equilibria>Buffer Solution

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:

MEDIUM

Chemistry>Physical Chemistry>Further Aspects of Equilibria>Buffer Solution

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]

EASY

Chemistry>Physical Chemistry>Further Aspects of Equilibria>Buffer Solution

Among the following, the correct statement is

HARD

Chemistry>Physical Chemistry>Further Aspects of Equilibria>Buffer Solution

The negative logarithm of dissociation constant of

{NH}_{4} OH

4.745

. A buffer solution contains

0.035

mole

{NH}_{4} OH

and

0.35

mole

{NH}_{4} Cl

per litre. The

pH

of the buffer solution is

EASY

Chemistry>Physical Chemistry>Further Aspects of Equilibria>Buffer Solution

If the molar concentrations of base and its conjugate acid are same, then

pOH

of the buffer solution is

MEDIUM

Chemistry>Physical Chemistry>Further Aspects of Equilibria>Buffer Solution

Which among the following pairs is not an acidic buffer?

MEDIUM

Chemistry>Physical Chemistry>Further Aspects of Equilibria>Buffer Solution

An acidic buffer is obtained on mixing:

MEDIUM

Chemistry>Physical Chemistry>Further Aspects of Equilibria>Buffer Solution

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:

EASY

Chemistry>Physical Chemistry>Further Aspects of Equilibria>Buffer Solution

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

Define buffer solution. What is it mainly used for?

Important Questions on Further Aspects of Equilibria

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