At T ( K ) , if the ionization constants of HCOOH and HCN are 2 . 0 × 10 - 4 and 5 . 0 × 10 - 9 , respectively, the ionization constants of the corresponding conjugate bases, respectively, are

5 . 0 × 10 - 11 , 2 . 0 × 10 - 6

2 . 0 × 10 - 6 , 5 . 0 × 10 - 11

2 . 0 × 10 - 4 , 5 . 0 × 10 - 9

5 . 0 × 10 - 9 , 2 . 0 × 10 - 4

MEDIUM

Earn 100

Statement I: The dissociation constants of polyprotic acid are in the order $k_{1} > k_{2} > k_{3} .$

Statement II: The $[H^{+}]$ furnished in the first step of dissociation exerts common ion effect to reduce the second dissociation and so on.

50% studentsanswered this correctly

Important Questions on Ionic Equilibrium

EASY

Chemistry>Physical Chemistry>Ionic Equilibrium>pH of Polybasic Acids or Polyacidic Bases

Ostwald's dilution law is applicable only for

MEDIUM

Chemistry>Physical Chemistry>Ionic Equilibrium>pH of Polybasic Acids or Polyacidic Bases

0.004 M

{Na}_{2} {SO}_{4}

is isotonic with

0.01 M

glucose solution. The degree of dissociation of

{Na}_{2} {SO}_{4}

EASY

Chemistry>Physical Chemistry>Ionic Equilibrium>pH of Polybasic Acids or Polyacidic Bases

Assuming that

Ba (OH)_{2}

is completely ionised in aqueous solution under the given conditions the concentration of

H_{3} O^{+}

ions in

0.005 M

aqueous solution of

Ba (OH)_{2}

298 K

is _________

\times 10^{- 12} mol L^{- 1} .

(Nearest integer)

EASY

Chemistry>Physical Chemistry>Ionic Equilibrium>pH of Polybasic Acids or Polyacidic Bases

The

pH

0.1 M

solution of acetic acid will be [degree of dissociation of acetic acid is

0.0132

]

MEDIUM

Chemistry>Physical Chemistry>Ionic Equilibrium>pH of Polybasic Acids or Polyacidic Bases

An aqueous solution in which the

H^{+}

ion concentration is greater than

10^{- 7} M

is said to be

EASY

Chemistry>Physical Chemistry>Ionic Equilibrium>pH of Polybasic Acids or Polyacidic Bases

K_{a}

values for acids

H_{2} {SO}_{3}, {HNO}_{2}, {CH}_{3} COOH

and

HCN

are respectively

1.3 \times 10^{- 2}, 4 \times 10^{- 4}, 1.8 \times 10^{- 5}

and

4 \times 10^{- 10},

which of the above acids produces stronger conjugate base in aqueous solution?

EASY

Chemistry>Physical Chemistry>Ionic Equilibrium>pH of Polybasic Acids or Polyacidic Bases

The acid dissociation constants of methanoic acid, monochloroethanoic acid and ethanoic acid are

K_{1}, K_{2}

and

K_{3}

respectively. If

K_{2} > K_{1} > K_{3}

, then

EASY

Chemistry>Physical Chemistry>Ionic Equilibrium>pH of Polybasic Acids or Polyacidic Bases

Match the following

Acid		Ionization constant, $K_{a}$
A)	Formic acid	I)	$4.9 \times 10^{- 10}$
B)	Niacin	II)	$1.5 \times 10^{- 5}$
C)	Hypochlorous acid	III)	$1.8 \times 10^{- 4}$
D)	Hydrocyanic acid	IV)	$3 \times 10^{- 8}$

The correct match is

MEDIUM

Chemistry>Physical Chemistry>Ionic Equilibrium>pH of Polybasic Acids or Polyacidic Bases

The

pH

of an aqueous solution of

10^{- 8} MHCl

MEDIUM

Chemistry>Physical Chemistry>Ionic Equilibrium>pH of Polybasic Acids or Polyacidic Bases

$0.01$ moles of a weak acid $HA (K_{a} = 2.0 \times 10^{- 6})$ is dissolved in $1.0 L$ of $0.1 M HCl$ solution. The degree of dissociation of $HA$ is __________ $\times 10^{- 5}$ (Round off to the Nearest Integer). [Neglect volume change on adding $HA$ and assume degree of dissociation $< < 1$ ]

MEDIUM

Chemistry>Physical Chemistry>Ionic Equilibrium>pH of Polybasic Acids or Polyacidic Bases

The degree of dissociation of

0.1 M

acid

HA

5 % .

The value of

K_{c}

HA

MEDIUM

Chemistry>Physical Chemistry>Ionic Equilibrium>pH of Polybasic Acids or Polyacidic Bases

The degree of dissociation of

0.1 N {CH}_{3} COOH

is (given

K_{a} = 1 \times 10^{- 5}

) approximately _________

HARD

Chemistry>Physical Chemistry>Ionic Equilibrium>pH of Polybasic Acids or Polyacidic Bases

Acetylsalicylic acid has

{pK}_{a}

value

3.5 .

The

pH

of gastric juice in human stomach is

2 - 3

and the pH in the small intestine is approximately

7.4 .

Then acetylsalicylic acid will be

MEDIUM

Chemistry>Physical Chemistry>Ionic Equilibrium>pH of Polybasic Acids or Polyacidic Bases

{CH}_{3} COOH

1 %

ionised in its aqueous solution of

0.1 M

strength. Its

pOH

will be

EASY

Chemistry>Physical Chemistry>Ionic Equilibrium>pH of Polybasic Acids or Polyacidic Bases

Match the following

List-1 Acid		List-2 Ka(ionization constant)
A)	$HCN$	I)	$6.8 \times 10^{- 4}$
B)	$H_{2} C_{2} O_{4}$	II)	$8.9 \times 10^{- 8}$
C)	$H_{2} S$	III)	$4.9 \times 10^{- 10}$
D)	Niacin	IV)	$5.6 \times 10^{- 2}$
		V)	$1.5 \times 10^{- 5}$

The correct match is

MEDIUM

Chemistry>Physical Chemistry>Ionic Equilibrium>pH of Polybasic Acids or Polyacidic Bases

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$ .

Assertion $A$ :Phenolphthalein is a $pH$ dependent indicator, remains colourless in acidic solution and gives pink colour in basic medium

Reason $R$ : Phenolphthalein is a weak acid. It doesn't dissociate in basic medium.

In the light of the above statements, choose the most appropriate answer from the options given below

MEDIUM

Chemistry>Physical Chemistry>Ionic Equilibrium>pH of Polybasic Acids or Polyacidic Bases

The

pH

0.1 M

acetic acid solution is closest to [Dissociation constant of the acid,

K_{a} = 1.8 \times 10^{- 5}

]

HARD

Chemistry>Physical Chemistry>Ionic Equilibrium>pH of Polybasic Acids or Polyacidic Bases

Sulphurous acid

(H_{2} {SO}_{3})

has

{Ka}_{1} = 1.7 \times 10^{- 2}

and

{Ka}_{2} = 6.4 \times 10^{- 8} .

The

pH

0.588 M H_{2} {SO}_{3}

is____________

(

Round off to the Nearest Integer

)

MEDIUM

Chemistry>Physical Chemistry>Ionic Equilibrium>pH of Polybasic Acids or Polyacidic Bases

T (K)

, if the ionization constants of

HCOOH

and

HCN

are

2.0 \times 10^{- 4}

and

5.0 \times 10^{- 9}

, respectively, the ionization constants of the corresponding conjugate bases, respectively, are

EASY

Chemistry>Physical Chemistry>Ionic Equilibrium>pH of Polybasic Acids or Polyacidic Bases

The degree of dissociation of $0 .1 mol L^{- 1}$ acetic acid in water is

( $K$ of acetic acid is $10^{- 5}$ )

Statement I: The dissociation constants of polyprotic acid are in the order k1 > k2 > k3. Statement II: The [H+] furnished in the first step of dissociation exerts common ion effect to reduce the second dissociation and so on.

Important Questions on Ionic Equilibrium

Learn and Prepare for any exam you want !

Statement I: The dissociation constants of polyprotic acid are in the order $k_{1} > k_{2} > k_{3} .$

Statement II: The $[H^{+}]$ furnished in the first step of dissociation exerts common ion effect to reduce the second dissociation and so on.