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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: hiswifetheirmom on November 08, 2009, 11:32:37 AM

Title: Acetic acid vs. Hydrochloric acid
Post by: hiswifetheirmom on November 08, 2009, 11:32:37 AM

Tell why vinegar (0.8M acetic acid) reacts much more slowly with zinc and marble chips than 0.8M hydrochloric acid, even though both acids have about the same total concentrations?

Title: Re: Acetic acid vs. Hydrochloric acid
Post by: cth on November 08, 2009, 12:28:49 PM

Because HCl is a strong acid, while acetic acid is a weak acid.

Strong acid are completely deprotonated in water: you find Cl^- and H₃O⁺ floating around in solution, but no undissociated HCl.

Weak acids are not completely deprotonated in water: you have an equilibrium between CH₃CO₂H and CH₃CO₂^-. Therefore, some part of the acetic acid can't react with zinc. The reaction is slower.

Title: Re: Acetic acid vs. Hydrochloric acid
Post by: tinapratiwi on November 12, 2009, 04:31:29 AM

yes thats true cth....
I agree with you... :D