MyQuestionIcon

1

You visited us 1 times! Enjoying our articles? Unlock Full Access!

Basic Buffer Action

Find the pH o...

Question

Find the $p H$ of $1 L$ of a buffer solution containing $0.01 M N H_{4} C l$ and $0.05 M N H_{4} O H$ at $25^{\circ} C$
The base dissociation constant for $N H_{4} O H$ is $1.8 \times 10^{- 5}$
Take $l o g (1.8) = 0.26$

A

9.96

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses

B

10.36

No worries! We‘ve got your back. Try BYJU‘S free classes today!

C

11.56

No worries! We‘ve got your back. Try BYJU‘S free classes today!

D

12.56

No worries! We‘ve got your back. Try BYJU‘S free classes today!

Open in App

Solution

The correct option is A 9.96
This is a basic buffer formed by a weak base $(N H_{4} O H)$ and its salt $(N H_{4} C l)$ with strong acid $(H C l)$
$p K_{b} = - l o g (K_{b}) p K_{b} = - l o g (1.8 \times 10^{- 5}) p K_{b} = (5 - 0.26) = 4.74$
$p O H = p K_{b} + l o g \frac{[s a l t]}{[b a s e]} p O H = p K_{b} + l o g (\frac{[N H_{4} C l]}{[N H_{4} O H]}) p O H = 4.74 + l o g (\frac{0.01}{0.05}) p O H = 4.74 + l o g (0.2) = (4.74 - 0.7) p O H = 4.04 p H + p O H = 14 p H = 14 - p O H = 14 - 4.04 = 9.96$

Suggest Corrections

thumbs-up

1

Similar questions

Q. Calculate the

p H

0.1 M

N H_{4} C l

solution in water :

K_{b} (N H_{4} O H) = 1.8 \times 10^{- 5}, l o g 1.8 = 0.25

p H

1 L

of a buffer solution containing

0.01 M N H_{4} C l

0.05 M N H_{4} O H

25^{\circ} C

The base dissociation constant for

N H_{4} O H

1.8 \times 10^{- 5}

l o g (1.8) = 0.26

Q. A buffer solution of

p H = 5.74

is to be prepared using

C H_{3} C O O H

C H_{3} C O O N a

. Find the concentration of sodium acetate to be added to

0.01 M

C H_{3} C O O H

K_{a} (C H_{3} C O O H) = 1.8 \times 10^{- 5}

l o g (1.8) = 0.26

Q. What will be the new

p H

0.01 m o l

N a O H

1 L

buffer solution that is

0.1 M

(C H_{3} C O O H)

0.1 M

in sodium acetate

(C H_{3} C O O N a)

?
Dissociation constant

K_{a}

of acetic acid at

25^{\circ} C

1.8 \times 10^{- 5}

Q. Freshly precipitated

A l

M g

hydroxides are stirred vigorously in a buffer solution containing

0.25 M

{N H}_{4} C l

0.05 M

{N H}_{4} O H

[{A l}^{3 +}]

[{M g}^{2 +}]

in solution are:
Given:

K_{b}

{N H}_{4} O H = 1.8 \times 10^{- 5}

K_{{s p}_{A l {(O H)}_{3}}} = 6 \times 10^{- 32}

K_{{s p}_{M g {(O H)}_{2}}} = 8.9 \times 10^{- 12}

View More

Join BYJU'S Learning Program

explore_more_icon

Explore more

Basic Buffer Action

Standard XII Chemistry

Join BYJU'S Learning Program

CrossIcon