equiv question

[BoneMental]

Advertisement - Members don't see this ad

IF you have add equivalent amounts of carbonic acid and calcium hydroxide, what's the pH of the solution going to be?

I said basic because carbonic acid is a weak acid and calcium hydroxide is a strong base....

The answer is neutral.

I think they're wrong. What do you guys think?

 

[attixx]

I'd like a little clarification on this as well. I almost answered saying that any acid + base will result in complete neutralization.

TPR seems to contradict itself in the section on this, however:

"If a strong acid and strong base react, the resulting solution will be pH neutral (which is why we call it a neutralization reaction). However, if the reaction involves a weak acid or a weak base, the resulting solution will generally not be pH neutral."

But in the question at the end of the section:

"Binary mixtures of equal moles of which of the following acid-base combinations will lead to a complete neutralization reaction?
I. HCl and NaOH
II. HF and NH3
III. HNO3 and NaHCO3"

The answer is all three, and solution states:
"Remember, regardless of the strengths of the acids and bases, all neutralization reactions go to completion."

That seems to go against what it said earlier about weak acids and bases. I could be misinterpreting something, so any clarification would be great.

 

[Rabolisk]

Regardless of the strength of acid or base, reactions of equimolar acid and base will always lead to a complete neutralization reaction. The pH need not be 7 at end.

 

[BoneMental]

I know equimolar amounts lead to neutralization, but the pH doesn't always equal 7.

Kaplan says that equimolar carbonic acid and calcium hydroxide leads to a neutral solution. I think this is wrong?

 

[attixx]

Regardless of the strength of acid or base, reactions of equimolar acid and base will always lead to a complete neutralization reaction. The pH need not be 7 at end.

I guess I was confusing "complete neutralization" as synonymous with pH=7.

Does that confirm that the answer given was an error in BoneMental's problem?

 

[Rabolisk]

That answer is wrong. Bicarbonate ion is slightly basic.

 

[flodhi1]

IF you have add equivalent amounts of carbonic acid and calcium hydroxide, what's the pH of the solution going to be?

I said basic because carbonic acid is a weak acid and calcium hydroxide is a strong base....

The answer is neutral.

I think they're wrong. What do you guys think?

I would assume that the solution would be basic. Weak acid + Strong Base = High pH.

 

[BoneMental]

Yay, I like being right! Thanks guys.