Home Cosmetic Science Talk Formulating mixed acid phosphoric and oxalic, and “common ionic effect”?

  • mixed acid phosphoric and oxalic, and “common ionic effect”?

    Posted by oldman20 on December 25, 2023 at 2:49 am

    i mixed acid phosphoric 85% (aq) with acid oxalic (crystal form, solved in water first - phase A) => phase B. The problem is:

    Phase A is transparent, like water. and phase B asa switch from transparent to clear lemon yellow

    Is it abnormally? Maybe crystal form of acid oxalic has impurities?

    And one thing impotant: It is possible to accelerate the reaction with metal when added to NaCl due to the phenomenon of “common ionic effect”: it provides Cl- ion to the solution, then Cl- combined with H+ in acid solution-> HCl

    is it true? Many thank

    oldman20 replied 11 months, 2 weeks ago 2 Members · 3 Replies
  • 3 Replies
  • oldman20

    Member
    December 26, 2023 at 3:05 am

    i found reason, clear yellow appears if i use acid phosphoric Korea, which has lightly purple color, while use others acid phosphoric which transparently, solution will stay transparent

    Now only question: common ionic effect. any help? Thank

  • chemicalmatt

    Member
    December 27, 2023 at 9:58 am

    @oldman20 Are you attempting to make a stainless steel surface cleaner here? Sounds like it. Forget the NaCl vector, it will not help. Oxalic acid alone works well; beefed up with phosphoric even better.

    • oldman20

      Member
      January 12, 2024 at 10:30 pm

      i trying make solution for remove calcium rust. Tested oxalic acid and compare with citric acid, seem citric work better (i used egg shield for test!)

      So it not correct?

      NaCl is possible to accelerate the reaction with metal when added to NaCl due to the phenomenon of “common ionic effect”: it provides Cl- ion to the solution, then Cl- combined with H+ in acid solution-> HCl

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