An acidic buffer is obtained on mixing :
1. 100 mL of 0.1 M CH3COOH and 100 mL of 0.1 M NaOH.
2. 100 mL of 0.1 M HCl and 200 mL of 0.1 M NaCl.
3. 100 mL of 0.1 M HCl and 200 mL of 0.1 M CH3COONa.
4. 100 mL of 0.1 M CH3COOH and 200 mL of 0.1 M NaOH.

Subtopic:  Buffer |
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Level 3: 35%-60%
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An aqueous solution of 1M NaCl and 1M HCl is : 

1. not a buffer but pH < 7 

2. not a buffer but pH >7 

3. a buffer with pH <7 

4. a buffer with pH >7 

Subtopic:  Buffer |
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A 25 mL buffer solution is prepared by mixing CH3COOH of concentration 0.1 M and CH3COONa of concentration 0.01 M. If the pH of the solution is 5, then the pKa of CH3COOH is:
1. Four (4)
2. Five (5)
3. Six (6)
4. Seven (7)
Subtopic:  Buffer |
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When 50 mL, 0.1 M CH3COOH (aq.) is titrated with 25 mL of 0.1 M NaOH (aq) solution. What is the value of the pH of the resulting solution?

[Given: pKa=4.76]

1. 3.76
2. 6.76
3. 4.76
4. 5.76
Subtopic:  pH calculation | Buffer |
Level 4: Below 35%
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A student is tasked with preparing a buffer solution using propanoic acid and its sodium salt to achieve a pH of 4. The required ratio of \(\frac{\left[\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{COO}^{-}\right]}{\left[\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{COOH}\right]}\) for the buffer is:
(Given that the \(\mathrm{K}_{\mathrm{a}}\left(\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{COOH}\right)=1.3 \times 10^{-5}\))
1. 0.13 2. 0.03
3. 0.23 4. 0.33
Subtopic:  Buffer |
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Class XII students were asked to prepare one litre of buffer solution of pH 8.26 by their Chemistry teacher. The amount of ammonium chloride to be dissolved by the student in \(\mathrm{0.2 ~M}\) ammonia solution to make one litre of the buffer is :
\((Given : \mathrm{pK}_{\mathrm{b}}\left(\mathrm{NH}_3\right)=4.74, \text{Molar mass of }~\mathrm{NH}_3=17 \mathrm{g} \mathrm{mol}^{-1}, \text{Molar mass of}~ \mathrm{NH}_4 \mathrm{Cl}=53.5 \mathrm{~g} \mathrm{~mol}^{-1} )\)

1. \(\mathrm{5.30~g}\)
2. \(\mathrm{72.3~g}\)
3. \(\mathrm{107.0~g}\)
4. \(\mathrm{126.0~g}\)
Subtopic:  Buffer |
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A student needs to prepare a buffer solution of propanoic acid and its sodium salt with pH = 4. The ratio of \(\frac{\left[\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{COO}^{-}\right]}{\left[\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{COOH}\right]}\)required to make a buffer is:
Given : \(\mathrm{K}_{\mathrm{a}}\left(\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{COOH}\right)=1.3 \times 10^{-5} \)
1. 0.03
2. 0.13
3. 0.23
4. 0.33
Subtopic:  Buffer |
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Level 2: 60%+
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In order to prepare a buffer solution of \(\text{pH} =5.74,\) sodium acetate is added to acetic acid. If the concentration of acetic acid in the buffer is \(1.0~\text M,\) the concentration(M) of sodium acetate in the buffer is:
(Round off to the nearest integer)
[Given: \(pKa\) (acetic acid) \(= 4.74\)]
1. 20
2. 5
3. 15
4. 10
Subtopic:  pH calculation | Buffer |
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Level 2: 60%+
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Which of the following buffer solution will have a pH of 9.25?
(Given that \(pK_b\) of \(NH_3:4.75)\)
1. \(0.2 ~\mathrm{M} ~\mathrm{NH}_4 \mathrm{OH}(0.4 \ell)+0.1 ~\mathrm{M}~ \mathrm{HCl}(1 \ell) \)
2. \(0.4~ \mathrm{M} ~\mathrm{NH}_4 \mathrm{OH}(1 \ell)+0.1 ~\mathrm{M} ~\mathrm{HCl}(1 \ell) \)
3. \(0.5 ~\mathrm{M} ~\mathrm{NH}_4 \mathrm{OH}(0.5 \ell)+0.2 ~\mathrm{M} ~\mathrm{HCl}(0.5 \ell) \)
4. \(0.2 ~\mathrm{M} ~\mathrm{NH}_4 \mathrm{OH}(0.5 \ell)+0.1 ~\mathrm{M}~ \mathrm{HCl}(0.5 \ell)\)
Subtopic:  pH calculation | Buffer |
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