Round the result to the desired number of decimal places for accuracy, if necessary.<\/li>\n\n<\/ol>\n
Let’s examine an example to solidify the concept.<\/p>\n
Example:<\/b><\/p>\n
Given pK = 5 and pH = 3.5, find the percentage of compound X in the solution.<\/p>\n
Solution:<\/b><\/p>\n<\/p>\n- The equilibrium reaction is as follows: XH \u21cc X- + H+<\/li>\n
<\/p>\n
- Calculate the equilibrium constant: Ka = 10^-pK = 10^-5 = 0.00001<\/li>\n
<\/p>\n
- Calculate the concentration ratio: [X-] \/ [H+] = 10^(pH-pK) = 10^(3.5-5) = 0.003162<\/li>\n
<\/p>\n
- Percentage of compound X = 0.003162 \u00d7 100 = 0.3162%<\/li>\n
<\/p>\n
- Therefore, compound X constitutes approximately 0.3162% of the solution.<\/li>\n
\n<\/ol>\n
The Answer:<\/b> To find the percentage from given pK and pH value, use the equation [X-] \/ [H+] = 10^(pH-pK) and multiply the result by 100.<\/p>\n