+ Reply to Thread
Results 1 to 3 of 3

Thread: Acid and Base, the pH scale

  1. #1
    Join Date
    Sep 2001
    Location
    San Rafael, CA
    Posts
    3,292

    Acid and Base, the pH scale

    'pH = potential of Hydrogen in aqueous solutions.
    This seems to be the only simple scale comparing a whole range of chemicals in our life.
    It is a linear scale that runs from extreme acidic (0) to neutral (7) to extreme base or alkaline(14).
    Each whole pH number is 10 times less or more. The extremes at both ends of the scale are deadly chemicals.
    'A pH value of 4 is ten times more acidic than a pH of 5 and a hundred times (10 X 10) more acidic than a pH of 6. This holds true for values above 7: a pH 10 is 10 times more alkaline than pH9.' (epa.gov/acidrain/measure/ph)
    There must be a parallel scale for non-aqueous chemicals, but I'm not aware of it.

    Began looking into this, trying to find what the choices are for a commercial cleaning agent for the old sail track, which looks like patina bronze rather than stainless steel. bill@ariel231 suggested that it was still usable, and if he says so............!
    The search is powered by an imco fraudulently marketed popular cleaner called >simple green< which has in it at least one suspected human carcingen 2-butoxethenol, formaldehyde, and more than 90 (ninety) other chemical ingredients, yet the product is labeled as non-toxic and biodegradable - altho said label also contains a caution on its phosphorus content. The manufacturer does not disclose these chemicals on its product website. Assume the FDA/EPA is OK with this.
    The cleaner's pH is 9.5, which is about the same as other alkaline detergents like, say, Tide.

    The pH scale does not express toxicity or ingredients. It does put substances in an orderly progression - and gives it a human face.
    At least in this case begins an inquiry into a product for a job of work.
    Dicarboxylic acid, ie oxalic acid, in the form of BarKeepersFriend* is one available choice for removing rust stains on various surfaces. NavelJelly Rust Dissolver* is a phosphoric acid/isoprpyl alcohol mix.
    Will one of these work on the old stainless sailtrack? Should I mix up some oxalic powder and water which I've used with abandon in the past - is there an alkaline detergent/bleach that might work better? Safer? Easier? Just trying to shine up a bit of ancient 304.

    Dawn Dish Detergent (pH7.44) is made from ethanol which is neither acid or base unless water is added. White vinegar(pH2.4) also starts life with ethanol.
    Theoretically you could take hydrochloric acid(pH0.0) and mix it with sodium hydroxide(pH14.0) and get a seven(pH7). Might explode before neutralizing.
    Acetone has the same pH as distilled water. Dawn dish 'soap', Ivory dish 'soap' and human blood share the same 7.4pH. The pH of water changes with temp getting more 'acid' with heat. And a chemical mixed with water can become acidic or base. Confused? That's not 0.001% of it.

    ..........ACID.....................pH............. ...........BASE.............
    0.0 hydrochloric acid..........................14.0 sodium hydroxide
    1.0 battery acid.................................13.0 lye
    1.0 gastric acid..................................12.0 chlorine bleach
    1.4 oxalic acid...................................12.0 TSP
    2.0 lemon juice.................................12.0 Liquid Plummer
    2.4 white vinegar...............................11.0 ammonia
    2.6 Coke...........................................10. 0 milk of magnesia
    3.6 Dr Pepper....................................9.9 toothpaste
    4.5 tomatoes.....................................9.5 detergents in water
    5.0 pickle juice..................................9.5 Borax
    5.8 BeptoBismol................................9.5 simple greeen
    6.0 urine..........................................8.5 sea water
    6.2 hydrogen peroxide.......................8.3 baking soda
    6.2 OxyClean....................................8.0 eggs
    6.6 root beer....................................7.44 Dawn Dish
    6.8 skim milk...................................7.4 human blood
    7.0 distilled water.............................7.0
    7.0 acetone
    [not comparing across dotted lines. Only way (for me) to get two columns.]

    At the extreemes, the VERY basic and VERY acidic are refered to as "REACTIVE".
    Battery acid and drain cleaners are reactive.
    SodiumHydroxide dissoves hair - and aluminum.
    Concentrated (35%) hydrogen peroxide (pH3.5) will severely burn skin and mucous membrane.
    Doctor Pepper is injurious to your teeth and diet with a pH3.6.
    This is an example of how the pH scale is secondary to the inherent properties of corrosive chemicals.
    If acetone(pH7.0) was served up to me as water(pH7.0) - my response would definitely be 100% REACTIVE.
    A more potent concentration of an acid in H2O gets a more extreme (lower) pH number
    A more potent concoction of an alkali in H2O gets a more exreme (higher) pH.


    With what then to strip the old stainless track? Acid or alkali? Oxalic acid(pH1.4), in the literature I've been looking at, is said to be "3000 times more potent than lemon juice(pH2.0)."
    And oxalic acid is generally used to remove iron stains, sometimes called rust. Will first try Barkeeper's Friend. Has the same pH as
    oxalic acid(pH 1.4) and comes in a convenient form. If that doesn't work I'll try toothpaste or milk of magnesia from the other side of the scale.
    On the >simple green thread< Craig recommends his acid/alkali choices as white vinegar and DawnDish. Certainly will stay out of trouble with those!
    Add maybe a nylon scotchbrite pad or two. OOPS, not on the lexan!
    __________________________________________________ __________________________________________________ ____________
    The 2pH and rinse gang:
    *BarKeepersFriend, Servaas Labs, 12oz bonami-style powder in 'cardboard can'. Less than $3. MSDS says a slurry will have pH of 1.5 to 2.5. My math figures it has 2/3 of an ounce of OXALIC ACID in the 12oz container of unknown white powder. It has the look of a normal scouring powder but directions say, sprinkle onto wet surface, rub gently with wet sponge, rinse thoroly within one minute of applying, wipe dry. No grit, good for s.s. sinks.
    *NavalJellyRustDissolver, pH2 (Loctite, Henkel,Duro), plastic bottle 8 - 16oz, approx $3. PHOSPHORIC ACID/Isopropyl Alcohol - pH2. Apply and rinse within 15min..
    [Duro AluminumJelly, pH2 -same ingredients as N.Jelly]
    [Alumiprep33 acidetch wash, same pH2, phosphoric acid/different alcohol. Apply and rinse within 2 min.]
    Last edited by ebb; 12-16-2011 at 01:43 PM.

  2. #2
    Join Date
    Nov 2009
    Location
    Brooklyn, NY
    Posts
    465

  3. #3
    Join Date
    Sep 2001
    Location
    San Rafael, CA
    Posts
    3,292

    Monona Rosso for President ! ! !

    Sorry, ebb went off his noodle on a subject he knows very little about. Erased it.
    Suggest your research start with the NRDC environmental action group.
    And with groups concerned with the effect environmental chemicals are having on women and children.
    Last edited by ebb; 12-15-2011 at 06:46 AM.

+ Reply to Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts