[kissoftalons]

Two questions.

1. Identify the Bronsted-Lowry acid, base, conjugate acid, and conjugate base for the following :"
NaHSO4 + NaHCO3 --> NaSO4 2- + H2CO3

My answer: The acid is NaHSO4 and the base would be NaHCO3, and then NaSO4 is the base and H2CO3 is the acid.
What does conjuage acid/base pairs mean? I thought you could only have a pair if it was an acid and a base. The question only asks for conjuage bases.

2. Write chemical equations to show that NaHCO3 is amphoteric.

I don't know how to approach this, but NaHCO3 is used in the equation above as a base (I think), how do I determine when its acting as an acid or a base?

[Donaldson Tan]

What does conjuage acid/base pairs mean? I thought you could only have a pair if it was an acid and a base. The question only asks for conjuage bases.

the conjugate base of an acid is usually the converted acid on the product side of the equation. it is a base because it can accept a proton.

eg. HSO₄^- <->  H⁺ + SO₄^2-
HSO₄^- is capable of donating a proton, so it's an acid. It's conjugatge base is SO₄^2- which is capable of accepting a proton

2. Write chemical equations to show that NaHCO3 is amphoteric.

amphoteric means capable of acting as both an acid & base.
you need 1 equation to show NaHCO3 donating a proton and another equation to show NaHCO3 accepting a proton.

[kissoftalons]

I think I've worked out the answers...after reading some lectures online about Acids and Bases. Can someone Confirm my answers?

1. NaHSO4 + NaHCO3 --> Na2SO4 (2-) + H2CO3
 Acid(1)     Base(1)       Base(2)         Acid(2)

Conjugate Pairs: Acid(1) and Base(2) and Acid(2) and Base(1)

2. Two equations to show that NaHCO2 is amphoteric.
Acting as an Acid: HCO3 + OH --> CO3 (2-) + H2O
Acting as a Base: HCl + NaHCO3 --> H2CO3 + NaCl

Acids are proton donors...So NaHCO3 donating a proton would result in CO3 (2-) making it act like an acid

Bases are proton acceptors ... So NaHCO3 accpeting a proton would result in H2CO3.

Is this correct?

[Borek]

Is this correct?

Seems you get the idea, but it will be much better to write net ionic equations, as this way you will concentrate on what is really going on.