Strong Bases

[Sophia Spungin 2E]

Hello! I am looking for some clarification on what classifies as a strong base. According to Sapling learning, only LiOH, NaOH, KOH, RbOH, CsOH, Ca(OH)2, Sr(OH)2 and Ba(OH)2 are strong bases. However, in the textbook as well as in lecture, group 1 and 2 oxides are listed as strong bases as well as Group 1 hydroxides and alkaline earth metal hydroxides. While I assume that we would go off of what was presented in lecture as well as what is stated in the textbook, I thought I should double check as well as inquire about why oxides are not included in the Sapling list?

[Can Yilgor 2D]

Hi! Strong bases are bases that are completely ionized in water. As you mentioned, group 1 (alkali metal) and group 2 (alkaline earth metal) oxides and hydroxides are considered as strong bases. The list of strong bases may be different in different resources, so I assume we are mainly responsible for the ones we have discussed in lectures. Also, instead of memorizing the list of strong bases, I recommend thinking about the chemistry behind it. How oxide ions, O2- react with water to form 2 moles of OH-.

Hope this helps :)

[Marcus Lagman 2A]

Hello!

As you know, according to the Arrhenius definition, a strong base is a base that completely dissociates in water to produce a cation and a hydroxide ion. From this definition, it is why Alkali Metals and Alkaline Earth Metals with a hydroxide are strong bases.

Although basic oxides do not contain a hydroxide group, they would still dissociate and form a hydroxide group and a cation when reacting with water. As a result, I would classify these still as strong bases. Examples would include Alkali Metals and Alkaline Earth Metals with oxides.

Here is a website with all of the strong bases and acids too! https://chem.libretexts.org/Bookshelves/General_Chemistry/Book%3A_ChemPRIME_(Moore_et_al.)/11%3A_Reactions_in_Aqueous_Solutions/11.09%3A_Strong_Acids_and_Bases

I hope this helps!

[Mirren Solomon Discussion 2G]

Is there any difference between a strong lewis acid and a strong bronstead acid? I know that the definition differs between the two but I was wondering if that changes the strong bases?

[Lauren Sarigumba 1K]

I learned a mnemonic my friend made up in order to memorize the strong bases more easily. Lily and Nate Robbed a Bank and Killed a Cesium of Strong Cats. (Li, Na, Rb, K, Cs, Sr, Ca).