Weak vs. Strong Acids and Bases

[Carolina Gomez 2G]

How do we identify when solving for pH when the equation deals with strong acids/ bases or weak acids/ bases?

[Xinyu Li 1C]

There is a list of strong acids and bases in the textbook. But generally, strong acids will contain halogens (Cl, Br, I) and strong bases will contain elements from group 1 & 2 (Li, Na, K, Rb, Cs, Ca, Sr, Ba).

https://sites.google.com/site/chempendi ... #h.p_ID_32

[Tracey Huynh 2F]

Xinyu's link is a great resource, where strong acids and bases completely dissociate when reacting with water, in which the [H30+] or [OH-] would be equivalent to the concentrations of the strong acids or bases. [H30+] and [OH-] can then be used to solve for pH. Otherwise, with weak acids and bases, the problem will usually provide us with an initial condition of the acid and the Kb or Ka value, which we can use to determine the concentration of [H3O+] or [OH-]. I believe that for the 6D problems in the textbook, the book requires you to utilize tables 6C.1 and 6C.2 for the Ka, Kb, pKa, and pKb values for certain weak acids and bases.

[Kathy_Li_1H]

Hi! For me to remember the strong acids and bases, I find it easiest to just use quizlet/flash cards to memorize them. Since there are a lot less strong acids and bases than their weak counterparts, I would just suggest knowing the strong acids and bases rather than trying to memorize the weak acids and bases.

Strong Acids: HCl, HBr, HI, HClO3, HClO4, HNO3, H2SO4
Strong Bases: Group 1 hydroxides, Ca(OH)2, Sr(OH)2, Ba(OH)2, Group 1 and 2 oxides

[Kelly Singh]

There is a list of strong acids and bases in the textbook. But generally, strong acids will contain halogens (Cl, Br, I) and strong bases will contain elements from group 1 & 2 (Li, Na, K, Rb, Cs, Ca, Sr, Ba).

https://sites.google.com/site/chempendi ... #h.p_ID_32

Thank you for this.

[jessicasilverstein1F]

Unfortunately the only way to know whether something is a strong/weak acid/base is to memorize them!

[Felicia Wei 1B]

You will know when something is a weak base or acid in an equation when the product consists of the ions that form those acids/bases. for example HCl will form H3O+ and Cl-

[Tanner Bartyczak 1K]

Yes, sadly it is almost necessary to memorize them, but there are a list of rules that are followed by most strong acids and bases.

[Gustavo_Chavez_1K]

I would say that the only and probably easiest way is to just memorize the list of strong acids and bases. With this all the acids and bases that aren't listed as strong would be considered weak.

[Arnav Saud 2C]

The best method is to memorize all of the strong acids and strong bases. Everything else is considered as a weak acid or base.