The dissociation constant of ethanoic acid (ch3cooh) at 298k is 1.8*10^-5 in a buffer solution the concentration of ch3coo and ch3cooh are 0.05m and 0.1m respectively what is the ph of the buffer solution
To calculate the pH of a buffer solution, we can use the Henderson-Hasselbalch equation:
pH = pKa + log ([A-] / [HA])
Where:
pH is the pH of the buffer solution
pKa is the logarithmic value of the acid dissociation constant (Ka) of the acid component (HA) of the buffer
[A-] is the concentration of the conjugate base (A-) of the acid component
[HA] is the concentration of the acid component (HA)
In this case,
pKa = -log10(Ka) = -log10(1.8 * 10^-5) = 4.74 (rounded to 2 decimal places)
[A-] = 0.05 M (concentration of CH3COO-)
[HA] = 0.1 M (concentration of CH3COOH)
Now, we can substitute the values into the Henderson-Hasselbalch equation to find the pH:
pH = 4.74 + log (0.05 / 0.1)
pH = 4.74 + log (0.5)
pH = 4.74 - 0.30
pH = 4.44 (rounded to 2 decimal places)
Therefore, the pH of the buffer solution is approximately 4.44.
To find the pH of the buffer solution, we need to calculate the ratio of the concentration of the conjugate base (CH3COO-) to the concentration of the acid (CH3COOH). This ratio is known as the Henderson-Hasselbalch equation and can be calculated using the formula:
pH = pKa + log([CH3COO-] / [CH3COOH])
Here, pKa is the negative logarithm of the acid dissociation constant (Ka) of the acid, which is equal to the dissociation constant for CH3COOH.
First, let's find the pKa of ethanoic acid using the equation:
pKa = -log(Ka)
Given that the dissociation constant (Ka) of ethanoic acid is 1.8 * 10^-5, we can calculate the pKa as follows:
pKa = -log(1.8 * 10^-5)
Next, substitute the values into the Henderson-Hasselbalch equation:
pH = pKa + log([CH3COO-] / [CH3COOH])
pH = pKa + log(0.05 / 0.1)
Now, you can calculate the pH using the given values:
pH = pKa + log(0.5)
Finally, using the calculated pKa and performing the logarithmic calculation, you can determine the pH of the buffer solution.