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acid/base definitions

Submitted by californianpeach on Mon, 04/26/2010 - 10:02

HCO3- + H2O H3O+ + CO32-

In this expression what is acting as the Bronsted-Lowry acid and the Bronsted-Lowry base? What is acting as the Arrhenius acid and the Arrhenius base?

Thanks.


bronsted-lowry theory states that:
a) acid is proton donor
b) base i proton acceptor

proton refers to free proton(H+) or sometimes written as water coordinated proton, ie H3O+; in essence both are the same.

Arrhenius defines,
a) acid is a substance that when dissolved in water increases the concentration of hydrogen ion, H+(aq).
b)a base is a substance that when added to water increases the concentration of hydroxide ion, OH-(aq).

So you want to make a smart guess?


So the bronsted-lowry base is H3O+ because it has accepted an H+ and the bronsted-lowry acid is HCO3-.

The arrhenius acid is HCO3- and the arrhenius base is H3O+.

Right?


californianpeach wrote:

So the bronsted-lowry base is H3O+ because it has accepted an H+ and the bronsted-lowry acid is HCO3-.

The arrhenius acid is HCO3- and the arrhenius base is H3O+.

Right?

you got it the other way around. HCO3- gain a proton in the forward reaction, so it is a base. whereas H3O+ donates the proton in this case, and proton donor is acid. But seriously, you must realise that hydroxium itself is the essence of hydrogen ion, the proton itself in water. ie it must be an acid!