In this lesson, you learned about acid-base theories.

Question

In this lesson, you learned about acid-base theories. For the following three reactions, identify the reactants that are Arrhenius bases, Brønsted-Lowry bases, and/or Lewis bases. State which type(s) of bases each reactant is. Explain your answers.

1. NaOH(s) → Na+(aq) + OH-(aq)

2. HF(aq ) + H2O(l) → F-(aq ) + H3O+(aq )

3. H+(aq ) + NH3(aq ) → NH4+(aq )

Answer 1

1. NaOH. Arrhenius base

    Na+

    OH-

any compound that contributes an OH- (hydroxide ion) when dissolved in water is by definition an Arrhenius. NaOH in an aqueous solution is therefore an Arrhenius Base

2. An example of Brnsted-Lowry base reaction, based on Lewis structure of bases having a lone pair of electrons to donate. In the reaction the number of hydrogens have increased from H2O to H3O

HF donates the H+ to the base H2O in aqueous solution forming H3O+ and F-. This type of reaction applies to both the Brnsted-Lowry and Lewis bases, where the former defines a base as any species that can accept a proton (H+) from an acid, and the latter  HF in aqueous solution is converted into Hyfdroflouric acid. The elements dissolve in water to produce F- and H3O (which accepted the proton from hydrogen fluoride (HF), or in other words the H2O accepted the proton not donating it which would have made it an acid in a different reaction.

3. Brnsted-Lowry (taking the Arrhenius reaction one step further in that water is not required to be present for the acid-base reaction to occur). The NH3 accepts the H+ thereby increasing the number of hydrogen sulfide in reaction determining it to be a base. Also Lewis Base applies.

 

NB each of these build on the other; Just as any Arrhenius acid is also a Brønsted acid, any Brønsted acid is also a Lewis acid, so the various acid-base concepts are all "upward compatible". Although we don't really need to think about electron-pair transfers when we deal with ordinary aqueous-solution acid-base reactions, it is important to understand that it is the opportunity for electron-pair sharing that enables proton transfer to take place. The exception here is if no proton is present.

"This as a very simplistic answer but to me the question doesnt seem to warrant a more in depth answer."