ammonia

[daniton]

is ammonia a bronsted or arrhenius acid or both????

[mississippichem]

What does it mean to be a Bronsted or Arrenhius acid? Ammonia has a lone pair of electrons about the nitrogen atom. How might that lone pair tend to interact with a proton?

 

I'm asking you these questions so you can think about the problem instead of merely receiving a pontificated answer.

 

Is this homework?

[weiming1998]

Ammonia has an extremely weak tendency to donate protons outside aqueous solution, forming amides and nitrides. Only extremely strong bases, like butyllithium (I think) can deprotonate ammonia. The pKa of ammonia is about 40, while the pKa of water is about 15-16.

Arrhenius acids donates protons in AQUEOUS SOLUTION, while if a substance can donate protons at all, it is a Bronsted-lowry acid. Now it's your turn to think.

Edited December 12, 2012 by weiming1998

[daniton]

by the way my question is really about the definition of arrhenius base because differnt books define it in differnt way sorry!!!!

[weiming1998]

An Arrhenius base is anything that increases the concentration of OH- in aqueous solution. In simpler terms, anything that causes the pH to rise above 7 when dissolved/mixed in water.

[hypervalent_iodine]

An Arrhenius base is anything that increases the concentration of OH- in aqueous solution. In simpler terms, anything that causes the pH to rise above 7 when dissolved/mixed in water.

 

 

Oooh, be careful with that. All Arrhenius bases increase the pH, but not all things that increase the pH are Arrhenius bases. Arrhenius definitions for acids and bases are really only taught for historical purposes and to lead into Bronsted-Lowry definitions rather than for their modern day practicality.