Dat bootcamp chem

[JDHK]

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Adding sodium oxalate to a solution of oxalic acid causes the pH to:

A. increase due to the common ion effect.
B. decrease due to the common ion effect.
C. remain constant because the resulting solution is a buffer.
D. increase due to shifting the Ka.
E. decrease due to shifting the Ka.

I put that it was C because it is a weak acid and its conjugate base which is a buffer? The answer is A. not quite sure why it cant be a buffer.

 

[jetset9]

It is a buffer, but even buffer solutions change in pH (i.e. even if you add the tiniest amount of acid, you'll still decrease the pH just a bit). So C is out.

 

[sakthivs]

so a buffer simply resists change, but it still undergoes a slight pH change no matter what right?

 

[jetset9]

Indeed!

 

[JDHK]

That's tricky =(. thank yaw!