A student prepared a 0.03M solution of formic acid (HCHO2) and measured its PH at 25oc and it was found to be 4.67. Calculate Ka for formic acid at this temperature.what percentage of the acid is ionized in this 0.03M solution.
To calculate the Ka for formic acid (HCHO2) at this temperature, we can use the pH value and the concentration of the solution. The Ka represents the acid dissociation constant and reflects the extent of ionization of the acid.
Step 1: Calculate the concentration of H+ ions in the solution using the pH value.
pH = -log[H+]
4.67 = -log[H+]
[H+] = 10^-pH
[H+] = 10^-4.67
Step 2: Calculate the percentage of ionization of the acid.
Ionization % = ([H+]/[HA]) * 100
[H+] represents the concentration of H+ ions determined in Step 1.
[HA] represents the original concentration of the acid solution, which is 0.03 M in this case.
% ionization = ([H+]/[HA]) * 100
% ionization = ([10^-4.67]/[0.03]) * 100
Step 3: Calculate Ka using the concentration of H+ ions determined in Step 1 and the percentage of ionization calculated in Step 2.
Ka = ([H+]^2) / [HA]
Ka = ([10^-4.67]^2) / [0.03]
Calculate the values for [10^-4.67] and substitute into the equation to find Ka.
Thus, the Ka for formic acid at this temperature can be calculated and it will depend on the values of [10^-4.67] and [0.03].
Please note that the calculation of [10^-4.67] and [0.03] will yield the exact value of Ka.