Photo AI

The pH of a 0.080 mol L⁻¹ solution of acetic acid is 2.9 - HSC - SSCE Chemistry - Question 20 - 2018 - Paper 1

Question icon

Question 20

The-pH-of-a-0.080-mol-L⁻¹-solution-of-acetic-acid-is-2.9-HSC-SSCE Chemistry-Question 20-2018-Paper 1.png

The pH of a 0.080 mol L⁻¹ solution of acetic acid is 2.9. What percentage of the acetic acid has dissociated into ions?

Worked Solution & Example Answer:The pH of a 0.080 mol L⁻¹ solution of acetic acid is 2.9 - HSC - SSCE Chemistry - Question 20 - 2018 - Paper 1

Step 1

Calculate the concentration of hydrogen ions (H⁺) using pH

96%

114 rated

Answer

To find the concentration of hydrogen ions, use the formula:

[H+]=10−pH[H^+] = 10^{-pH}

Substituting the given pH value:

[H+]=10−2.9≈0.00126 mol L−1[H^+] = 10^{-2.9} \approx 0.00126 \, mol \, L^{-1}

Step 2

Determine the initial concentration of acetic acid

99%

104 rated

Answer

The initial concentration of acetic acid, CC, is 0.080 mol L⁻¹.

Step 3

Use the dissociation formula to find the degree of dissociation

96%

101 rated

Answer

The degree of dissociation is given by:

α=[H+]C\alpha = \frac{[H^+]}{C}

Substituting the values:

α=0.001260.080≈0.01575\alpha = \frac{0.00126}{0.080} \approx 0.01575

Step 4

Convert to percentage of dissociation

98%

120 rated

Answer

To find the percentage, multiply by 100:

Percentage=α×100≈1.575%\text{Percentage} = \alpha \times 100 \approx 1.575\%

Thus, rounding to one decimal place gives approximately 1.6%.

Join the SSCE students using SimpleStudy...

97% of Students

Report Improved Results

98% of Students

Recommend to friends

100,000+

Students Supported

1 Million+

Questions answered

;