It's 7.2 times ten to negative four. And that means, according to this theory, it's a bad acid. And in fact, it is a bad acid. It's a weak acid. So now we can use this ka value to determine whether or not an acid is a good acid or a bad asset. Now, before we have to look at the polarity of the bond, we have to look at the bond strength and we have to look at the conjugate base.