quick gchem question

[polarmolar]

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Pyruvic acid is a weak acid. Which of the following is a likely pH for an aqueous solution of sodium pyruvate?​

A. 1.0

B. 6.0

C. 7.0

D. 8.0

E. 14.0

I got it this one right, but then again I am starting to think...isn't the conjugate base of a weak acid a strong base? Thus shouldn't the answer be 14?

thanks!

 

[ucla2134]

Pyruvic acid is a weak acid. Which of the following is a likely pH for an aqueous solution of sodium pyruvate?​

A. 1.0

B. 6.0

C. 7.0

D. 8.0

E. 14.0

I got it this one right, but then again I am starting to think...isn't the conjugate base of a weak acid a strong base? Thus shouldn't the answer be 14?

thanks!

ph 14 is for really strong base, like sodium hydroxide (which hydrolyze completely unlike the hydrolysis of weak base: A-+ H20<->HA +OH-). Although conjugate base of weak acid is strong, butHOP it is still a week base when comparing to a base that yield 14.
hope my explanation make sense to u

 

[utdent20]

so the answer is 8?

 

[xaznxcountx]

the answer is 8 because I did a problem very similar to this... 14 is too basic...

 

[polarmolar]

ph 14 is for really strong base, like sodium hydroxide (which hydrolyze completely unlike the hydrolysis of weak base: A-+ H20<->HA +OH-). Although conjugate base of weak acid is strong, butHOP it is still a week base when comparing to a base that yield 14.
hope my explanation make sense to u

Yea that makes sense, thanks.

 

[Danny289]

Pyruvic acid is a weak acid. Which of the following is a likely pH for an aqueous solution of sodium pyruvate?​

A. 1.0

B. 6.0

C. 7.0

D. 8.0

E. 14.0

I got it this one right, but then again I am starting to think...isn't the conjugate base of a weak acid a strong base? Thus shouldn't the answer be 14?

thanks!

1) Py-Na =========> (Na+) + (Py-)
2) H2O <==========> OH- + H+
H+ and Py- react because Pyruvic acid is a weak acid.
then in equation (2) in right side you are loosing H+ that means you have more OH- ======> OH-> H+======> solution basic this is principal but remeber salt makes weak base or weak acid and 14 is strong base. also check my other post. in DAT you don't need to know whole detail.
http://forums.studentdoctor.net/showthread.php?p=7019579#post7019579