## Weak Acids and Bases

Acidity $K_{a}$
Basicity $K_{b}$
The Conjugate Seesaw $K_{a}\times K_{b}=K_{w}$

Armani Dodson 1A
Posts: 24
Joined: Fri Jul 22, 2016 3:00 am

### Weak Acids and Bases

When we do the ice table and for the reactants at equilibrium, it is usually a value of like (0.2-x).... why are we able to ignore that x value???

Mimi Lec 2H
Posts: 29
Joined: Fri Jul 22, 2016 3:00 am

### Re: Weak Acids and Bases

Because we know it is a weak acid/base, we know that Ka is very small, so we can approximate, and basically set that x equal to 0. I think the rule is if the given Ka is smaller than 10^-4, you can safely approximate.

Joslyn_Santana_2B
Posts: 51
Joined: Wed Sep 21, 2016 2:58 pm

### Re: Weak Acids and Bases

It is actually if it's exponent is less than or EQUAL TO -4.

Ex: K_a= 3e^(-4), you can use the short cut to find x.