chenbeier

That would be better, you get only CO2, which will evaporate.

These are simple acid base reactions. HA + BOH => AB + H2O The stronger acid here bisulfate will push out the weak acid (Boric acid or silicon dioxide) and the salt (here sulfate) and water will be formed.

Borax would also alcalise the solution.

I would add more NaOH or Na2CO3, because the precipitation of SiO2 will be higher with adding silicate.

Sodium sulfate and silicon dioxide

EDTA-metal is a 1:1 complex. That mean for the alkaline-earth metals and most transitionmetals you need per mol metal two mol HCl. So you have to know the concentration of the EDTA and also roughly the metal concentration obtained by the titration.

The redox reaction between ethanol and manganese-VII-oxid is missing.

Check the redoxpotentiales. What do thing do you get a reaction with Mn and B2O3?

Finally you will have iron-III-acetate. Fe(CH3COO)3

Maybe this: https://www.google.com/search?q=ketopentose+ringform&client=firefox-b&tbm=isch&source=iu&ictx=1&fir=-v76lGvCZRYPvM%3A%2CBx9t22rEqeKo4M%2C_&usg=AI4_-kRdF7ma8ygSKaqu772wrqjAcUGfMQ&sa=X&ved=2ahUKEwihgYq9juHeAhWhw4sKHdtUCi4Q9QEwA3oECAAQCg#imgrc=-v76lGvCZRYPvM:

Nevertheless, In my opinion any chemical treatment will change the meat of the fish.

Maybe in this way -RCO-NHR- + H+ + H2O = -RCOOH + +NH3-R

After this treatment the fish is also not eatable anymore. HCl will destroy the aminoacids as well.

Add some chlorine or hypochlorite and convert all bromide to bromine.

I am not sure there will be a precipitation. I would precipitate nickel hydroxide from the sulfate and later after filtering and wasching do a neutralisation with boric acid.