“Why did the weak acid go to the gym?”/“To become a buffer solution.”

A chemistry joke has been printed on several images:
 
Q: Why did the weak acid go to the gym?
A: To become a buffer solution.
   
The riddle was posted on Twitter on October 16, 2010.
 
         
Twitter
Lee Jun Kit
@leejunkit
Joke: Why did the weak acid go to the gym?
To become a buffer solution.
5:03 AM - 16 Oct 2010
   
Twitter
Hazi
@hazysnaps
Replying to @annnivedha
HAHAHAH ANN! RT @annnivedha Why did the weak acid go to the gym? Because it wanted to be a buffer solution!
9:20 AM - 20 May 2011
   
Twitter
Wei Lin Low
@Weilinlow
To find a buffer solution ._. RT @SWEEYAN Why did the acid go to the gym?
11:20 PM - 27 Jul 2011
   
Twitter
Tang Zhi Yang
@SquirtleyT
Why did the weak acid go to the gym with his salt? To become a buffer solution.
9:23 PM - 11 Aug 2011
   
Twitter
Hui Xian
@huixianloves
Why did the amino acid go to the gym? To become a buffer solution.
5:32 AM - 21 Oct 2011
     
Twitter
Chemistry Jokes
@Funny_Chemistry
Why did the acid go to the gym?
He wanted to become a buffer solution.
8:59 PM - 15 Jan 2015
 
Facebook
ChemCentre
April 20, 2015 ·
Why did the acid go to the gym? To become a buffer solution! #chemjokeoftheweek #doyouevenlift
 
Reddit—Puns
Chemistry Puns (self.puns)
submitted April 30, 2017 by Punsville
Why did the acid go to the gym? To become a buffer solution!
 
Reddit—Jokes
Why did the jar of weak acid go to the gym.
submitted July 2, 2018 by mrbadassmotherfucker
To become a buffer solution