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

Calculate approximate [OH - ] and [H 3 PO 4 ] concentrations in a solution of 0.1 mole Na 3 PO 4 in one litre for H 3 PO 4 K a 1 = 7 . 1 × 1 0 - 3 M , K a 2 = 6 . 3 × 1 0 - 8 M , K a 3 = 4 . 5 × 1 0 - 1 2 M

H 3 PO 4 = 6 × 1 0 - 1 8 , OH - = 3 · 7 3 × 1 0 - 2 M

H 3 PO 4 = 6 × 1 0 - 1 6 , OH - = 3 · 7 3 × 1 0 - 4 M

H 3 PO 4 = 6 × 1 0 - 2 0 , OH - = 3 · 7 3 × 1 0 - 6 M

H 3 PO 4 = 6 × 1 0 - 1 8 , OH - = 1 3 · 7 3 × 1 0 - 2 M

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At $25 ° C p H$ , range of phenolphthalein is $8 - 10$ . At $100 ° C p H$ , range of phenolphthalein would be-

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Important Questions on Ionic Equilibrium

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Chemistry>Physical Chemistry>Ionic Equilibrium>Factors Affecting the Acid Strength

The solubility of

AgCl

will be maximum in which of the following?

EASY

Chemistry>Physical Chemistry>Ionic Equilibrium>Factors Affecting the Acid Strength

Ostwald's dilution law is applicable only for

EASY

Chemistry>Physical Chemistry>Ionic Equilibrium>Factors Affecting the Acid Strength

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?

MEDIUM

Chemistry>Physical Chemistry>Ionic Equilibrium>Factors Affecting the Acid Strength

The correct decreasing order of the basic strength is

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Chemistry>Physical Chemistry>Ionic Equilibrium>Factors Affecting the Acid Strength

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

MEDIUM

Chemistry>Physical Chemistry>Ionic Equilibrium>Factors Affecting the Acid Strength

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>Factors Affecting the Acid Strength

{CH}_{3} COOH

1 %

ionised in its aqueous solution of

0.1 M

strength. Its

pOH

will be

HARD

Chemistry>Physical Chemistry>Ionic Equilibrium>Factors Affecting the Acid Strength

K_{a}

for butyric acid

(C_{3} H_{7} COOH)

2 \times 10^{- 5}

. The

pH

0.2 M

solution of butyric acid is____

\times 10^{- 1}

. (Nearest integer) [Given

\log 2 = 0.30

]

MEDIUM

Chemistry>Physical Chemistry>Ionic Equilibrium>Factors Affecting the Acid Strength

$0.01$ 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 $< < 1$ ]

HARD

Chemistry>Physical Chemistry>Ionic Equilibrium>Factors Affecting the Acid Strength

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

)

EASY

Chemistry>Physical Chemistry>Ionic Equilibrium>Factors Affecting the Acid Strength

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

MEDIUM

Chemistry>Physical Chemistry>Ionic Equilibrium>Factors Affecting the Acid Strength

A soft drink was bottled with a partial pressure of

{CO}_{2}

of 3 bar over the liquid at room temperature. The partial pressure of

{CO}_{2}

over the solution approaches a value of 30 bar when

44 g

{CO}_{2}

is dissolved in

1 kg

of water at room temperature. The approximate

pH

of the soft drink is ___________

\times 10^{- 1}

.
(First dissociation constant of

H_{2} {CO}_{3} = 4.0 \times 10^{- 7}; \log 2 = 0.3;

density of the soft drink

= 1 g {mL}^{- 1}

)

MEDIUM

Chemistry>Physical Chemistry>Ionic Equilibrium>Factors Affecting the Acid Strength

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>Factors Affecting the Acid Strength

The initial rate of hydrolysis of methyl acetate

(1 M)

by a weak acid

(HA, 1 M)

1 / 100^{th}

of that by a strong acid

(HX, 1 M)

, at

25 ° C

. The

K_{a}

HA

EASY

Chemistry>Physical Chemistry>Ionic Equilibrium>Factors Affecting the Acid Strength

For

10^{- 2} (M) H_{3} {P O}_{3}

solution which of the following relations is correct?

HARD

Chemistry>Physical Chemistry>Ionic Equilibrium>Factors Affecting the Acid Strength

18 ° C

, the solubility of

CdS

in water is

6.33 \times 10^{- 15} M

. What is the concentration of

{Cd}^{+}

ion in a solution of

pH = 1

saturated with

H_{2} S

gas, in which cocentration of

H_{2} S = 0.1 M

? The product of the first and second ionization constants of

H_{2} S

1.1 \times 10^{- 22}

at this temperature.

HARD

Chemistry>Physical Chemistry>Ionic Equilibrium>Factors Affecting the Acid Strength

Calculate the ratio of

{HCOO}^{-}

and

F^{-}

in a mixture of

0.2 M HCOOH (K_{a} = 2 \times 10^{- 4})

and

0.1 M HF (K_{a} = 6.6 x 10^{- 4})

HARD

Chemistry>Physical Chemistry>Ionic Equilibrium>Factors Affecting the Acid Strength

Calculate approximate [OH^- ] and [H₃ PO₄ ] concentrations in a solution of 0.1 mole Na₃ PO₄ in one litre for H₃ PO₄

K_{a_{1}} = 7.1 \times 1 0^{- 3} M,

K_{a_{2}} = 6.3 \times 1 0^{- 8} M,

K_{a_{3}} = 4.5 \times 1 0^{- 12} M

HARD

Chemistry>Physical Chemistry>Ionic Equilibrium>Factors Affecting the Acid Strength

What volume (in mL) of concentrated

HCl

solution

(d = 1.18 g / mL)

containing

36 % HCl

by weight is required to produce

6.55 litres

of a solution with pH

1.85 ?

MEDIUM

Chemistry>Physical Chemistry>Ionic Equilibrium>Factors Affecting the Acid Strength

The degree of ionisation of a compound depends upon:

At 25°C pH, range of phenolphthalein is 8–10. At 100°C pH, range of phenolphthalein would be-

Important Questions on Ionic Equilibrium

Learn and Prepare for any exam you want !

At $25 ° C p H$ , range of phenolphthalein is $8 - 10$ . At $100 ° C p H$ , range of phenolphthalein would be-