If you're curious or actually knowledgeable about chemistry, here's what happened.
My apartment's dishwasher has gaps in the enamel from which rust can drip onto plates and silverware. I tried soaking but I presume to be a stainless steel knife with a drip of rust on it in citric acid. The rust turned black and the water turned a dark but translucent blue/purple.
replyI know nothing about chemistry. My smartest move was to not provide the color and ask what the color might have been. It never guessed blue or purple.
In fact, it first asked me if this was highschool or graduate chemistry. That's not... and it makes me think I'll only get answers to problems that are easily graded, and therefore have only one unambiguous solution
I'm a little confused by your question myself. Stainless steel rust should be that same brown color. Though it can get very dark when dried. Blue is weird but purple isn't an uncommon description, assuming everything is still dark and there's lots of sediment.
replyBut what's the question? Are you trying to fix it? Just determine what's rusting?
Oh yeah, the question is "can I use the knife and the glass again?"
replyAlthough, now that I look closely at them, the butter knife got eaten away in spots and it's already pretty cheap, so I'll toss it.
I'd answer "probably" if you've cleaned everything. But if the rust comes back then probably should just toss. Rust is an oxide layer, so outside only
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