percent ionization and protonation

[Emilia Yuja 3L]

Hello, I was wondering if the %ionization and the %protonation always be the ones used to check if we can approximate the x? I find myself using this number, so I want to make sure this is right.

[Anamika Patel 3I]

You can make the x is small assumption if the K values are less than 10^-3, but if you solve for protonation/ionization and the value is greater than 5, you should go back and solve for x without making the x is small assumption.