Chain broke

 was riding with a friend in town at night, when I accelerated HARD from a red light…
I went for 10 meters maybe and then the Rd felt as if it was in Neutral. Damn!
Couldn’t see a thing and since I was close to my house, I just parked it in the street.
Next morning I found my chain right at the red light, a link had burst open, several more were stretched.
I had derusted the chain a feww weeks before… never ever use Posphoric acid to treat chains!
Obviously, it fatigues the metal severely. The master link was still firmly attached to the chain…