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

Salt of Weak Acid and Strong Base

1.00 L of a b...

Question

$1.00 L$ of a buffer that is $0.100 M$ in $H O A c$ ( $p K_{a} = 4.74)$ and $0.100 M$ in $N a O A c$ . What is the pH after the addition of $0.0200 m o l$ $N a O H$ ? $(l o g 1.5 = 0.176)$

4.92

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

4.74

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

8.74

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

6.74

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

Open in App

Solution

The correct option is A 4.92
Consider the reaction of the strong base with the weak acid first. That reaction goes to completion.
$H O A c + O H^{-} \to H_{2} O + O A c^{-}$

$\begin{matrix} HOAc & O H^{-} & O A c^{-} Initial & 100.0 m m o l & 20.0 m m o l & 100.0 m m o l Change & - 20.0 m m o l & - 20.0 m m o l & + 20.0 m m o l End & 80.0 m m o l & 0 & 120.0 m m o l \end{matrix}$
Using Henderson's equation
$p H = p K_{a} + l o g (\frac{[A^{-}]}{[H A]})$
$p H = 4.74 + l o g (\frac{120.0}{80.0})$
$p H = 4.92$

Suggest Corrections

Similar questions

1.00 L

of a buffer that is

0.100 M

H O A c

(

p K_{a} = 4.74)

and

0.100 M

N a O A c

. What is the pH after the addition of

0.0200 m o l

N a O H

(l o g 1.5 = 0.176)

Q. 1L of a buffer is created to be

0.100 M

H O A c

. the

p K_{a} = 4.7

and

0.100 M

N a O A c

. What is the

p H

100

mL of

0.01

C H_{3} C O O H

and

200

mL of

0.02

C H_{3} C O O N a

are mixed to form a buffer solution.

700

mL of water is added to this solution. The pH before and after dilution are:
(pKa = 4.74, log 4 =0.6)

A weak acid, HA has a $K_{a}$ of $1.00 \times 10^{- 5} .$ If 0.100 mol of this acid is dissolved in one litre of water, the percentage of acid dissociated at equilibrium is closest to

Q. To

1.0 L

solution containing

0.1

mol each of

N H_{3}

and

N H_{4} C l, 0.05

mol NaOH is added. The change in pH will be :

(p K_{a}

for

C H_{3} C O O H = 4.74

)

Join BYJU'S Learning Program

Explore more

Salt of Weak Acid and Strong Base

Standard XI Chemistry

Join BYJU'S Learning Program

1.00 L of a buffer that is 0.100 M in HOAc (pKa=4.74) and 0.100 M in NaOAc. What is the pH after the addition of 0.0200 mol NaOH? (log 1.5=0.176)

$1.00 L$ of a buffer that is $0.100 M$ in $H O A c$ ( $p K_{a} = 4.74)$ and $0.100 M$ in $N a O A c$ . What is the pH after the addition of $0.0200 m o l$ $N a O H$ ? $(l o g 1.5 = 0.176)$