What is the pH of 1-5 L of vinegar that is 3 - acetic acid by mass - K a -1-8 - 10-5A- 12B- 7C- 4-3D- 2-5

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What is the pH of $1.5 L$ of vinegar that is 3% acetic acid by mass ? $(K_{a} = 1.8 \times 10^{- 5})$

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Solution

The correct option is D 2.5
Assume that the vinegar is really just a solution of acetic acid in water, and that density = $1 g m L^{- 1}$
So if the vinegar is 3% acetic acid by mass and the molar mass of $C H_{3} C O O H = 60.05 g m o l^{- 1}$ , then
$1.5 L v i n e g a r \times \frac{1000 m L}{1 L} \times \frac{1 g}{1 m L} \times \frac{3 g a c e t i c a c i d}{100 g v i n e g a r} \times \frac{1 m o l a c e t i c a c i d}{60.05 g a c e t i c a c i d} = 0.75 m o l C H_{3} C O O H$
Dividing $0.75 m o l$ by $1.5 L$ to get an initial concentration of 0.50 M,
considering the ionization of acetic acid in water into acetate ion and hydronium ion. ignoring the concentration of water (a pure liquid).
$C H_{3} C O O H_{(a q)} + H_{2} O_{(a q)} ⇌ C H_{3} C O O^{-} {2 (a q)}^{-} + H_{3} O_{(a q)}^{+}$
$\begin{matrix} C H_{3} C O O H & H_{2} O & C H_{3} C O O^{-} & H_{3} O^{+} I n i t i a l & 0.5 & . . . & 0 & 0 C h a n g e & - x & . . . & + x & + x E q u i l i b r i u m & 0.5 - x & . . . & x & x \end{matrix}$
the equilibrium constant expression
$K_{a} = \frac{[C H_{3} C O O^{-}] [H_{3} O^{+}]}{[C H_{3} C O O H]}$
$1.8 \times 10^{- 5} = \frac{[x] [x]}{[0.5 - x]}$
here x can be neglected because it is very small so, 0.5-x=0.5

$x = 0.003 M = [H_{3} O^{+}]$
put up into the formula
$p H = - log [H_{3} O^{+}] p H = - log (0.003) = 2.5$

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Similar questions

Q. What is the pH of a 1 M

C H_{3} C O O H

solution?

[

K_{a}

of acetic acid

= 1.8 \times 10^{- 5}, K_{w} = 10^{- 14} m o l^{2} l i t r e^{- 2}

]

Q. What is the pH of the solution when 0.2 mole of hydrochloric acid is added to one litre of a solution containing 1 M acetic acid and acetate ion? Assume that the total volume is one litre.

K_{a}

for

{CH}_{3} COOH = 1.8 \times 10^{- 5}

To what volume one litre of 0.1M acetic acid solution diluted so that the pH of the solution becomes double of the initial ? ( $K_{a} = 1.8 \times 10^{- 5}$ )

Q. What will be the new

p H

0.01 m o l

N a O H

is added to a

1 L

buffer solution that is

0.1 M

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(C H_{3} C O O H)

and

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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. Consider an acidic buffer solution of acetic acid and sodium acetate at

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{log}_{10} 1.8 = 0.25 and 10^{(0.25)} = 1.8

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pH the Power of H

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What is the pH of 1.5 L of vinegar that is 3% acetic acid by mass ? (Ka=1.8×10−5)

What is the pH of $1.5 L$ of vinegar that is 3% acetic acid by mass ? $(K_{a} = 1.8 \times 10^{- 5})$