Nitric acid, Copper and Zinc

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  • Опубліковано 17 вер 2024
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    3Cu + 6HNO3 = 3Cu(NO3)2 + 6H,
    3HNO3 + 6H = 3HNO2 + 3H2O,
    3HNO2 = HNO3 + 2NO + H2O,
    which gives, on summing up,
    3Cu + 8HNO3 = 3Cu(NO3)2 + 2NO + 4H2O.
    Divers considered that metals may be divided into two classes with reference to their action on nitric acid. In the first class are placed the four metals copper, silver, mercury, and bismuth, and the primary products are nitrite, nitrate, and water:
    1) 2Ag + HO.NO2 = AgOH + AgNO2;
    2) AgOH + HNO3 = AgNO3 + H2O.
    Further action of the nitric acid on the nitrite produces nitrous acid and nitrate:
    3) AgNO2 + HNO3 = AgNO3 + HNO2;
    while the nitrous acid reacts to produce nitrogen peroxide or nitric oxide according as the nitric acid is concentrated or dilute, as shown in the following equations: -
    4) HNO2 + HNO3 = 2NO2 + H2O;
    5) 3HNO2 = HNO3 + 2NO + H2O.
    Divers assumed that a very small quantity of nitrous acid is necessary to initiate the reaction and functions in a catalytic manner. There is no formation of ammonia or hydroxylamine at any stage of the reaction.
    The second class of metals includes zinc, magnesium, aluminium, cadmium, tin, lead, iron, and the alkali metals, and no nitrous acid is required to start their reaction with nitric acid. According to Divers, nitrous acid is not produced in appreciable amounts, because further reduction occurs which is due to the action of nascent hydrogen:
    HNO3 + 2H = HNO2 + H2O; (Nitrous acid.)
    2HNO3 + 8H = H2N2O2 + 4H2O; (Hyponitrous acid.)
    HNO3 + 6H = NH2OH + 2H2O; (Hydroxylamine.)
    HNO3 + 8H = NH3 + 3H2O. (Ammonia.)
    The production of hydroxylamine and ammonia occurs chiefly with tin and zinc, although under suitable conditions other metals may give traces. The nature and quantity of both primary and secondary products depend upon the concentration of the acid. Secondary products result from the following reactions: -
    3HNO2 = HNO3 + 2NO + H2O;
    H2N2O2 = N2O + H2O;
    HNO2 + NH2OH = N2O + 2H2O;
    HNO2 + NH3 = N2 + 2H2O.
    Thus the reduction products of nitric acid produced by zinc under various conditions may be shown in the following reactions: -
    3Zn + 7HNO3 = 3Zn(NO3)2 + NH2OH + 2H2O;
    4Zn + 9HNO3 = 4Zn(NO3)2 + NH3 + 3H2O;
    4Zn + 10HNO3 = 4Zn(NO3)2 + N2O + 5H2O;
    5Zn + 12HNO3 = 5Zn(NO3)2 + N2 + 6H2O.
    Veley suggests that nitrous acid is necessary to initiate the reaction between all metals and nitric acid, and his experiments go to prove that really pure nitric acid has no action on pure metals. There is considerable difficulty in obtaining complete purity of the reacting substances, and traces of nitrous acid are produced probably by electrolytic action set up by the most minute quantities of impurities in the metals. The very slight action of pure nitric acid of 30 per cent, concentration on pure metals was almost entirely prevented if the metals were agitated in the solution, because it was not possible for nitrous acid to concentrate round the metal. No action occurred at all if the formation of nitrous acid was inhibited by adding such substances as urea, hydrogen peroxide, potassium chlorate, etc. While Veley agrees that the metals copper, silver, mercury, and bismuth differ in their action from the rest of the metals, yet he maintains that in all cases nitrous acid is necessary to start the reaction, and that nitrous acid is the primary product in all cases. Thus, in the case of copper the reaction can be represented by the equations
    Cu + 4HNO2 = Cu(NO2)2 + 2NO + 2H2O,
    Cu(NO2)2 + 2HNO3 = Cu(NO3)2 + 2HNO2.
    The decomposition or formation of nitrous acid is shown by the reversible reaction
    3HNO2 ⇔ HNO3 + 2NO + H2O.
    In the case of both classes of metals Veley found that rapid solution occurred in nitrous acid, less rapid in a mixture of nitrous and nitric acids, and much slower action still in the case of pure nitric acid solution.
    The only metal which produces free hydrogen is magnesium, and the nitric acid must be very dilute. As magnesium is next to the alkali metals with regard to its high solution tension, Webb suggests that hydrogen is liberated first by all metals with a higher solution tension than hydrogen, while those with a lower solution tension (copper, mercury, silver) are polarised in a solution of nitric acid. The function of nitrous acid in starting the reaction between these metals and nitric acid is that of a depolariser.

КОМЕНТАРІ • 27

  • @arielkozak
    @arielkozak 2 роки тому

    This is actually very interesting and I learned something from watching. Thanks

    • @TheMrbunGee
      @TheMrbunGee  2 роки тому

      Glad to hear that! Good luck! :)

  •  6 років тому

    Would it be possible to draw an infographic diagram of what is going on, like in a tournament?
    A box which would say, "copper" then with an arrow with (-200C to 300C) and pressures and soforth that this reaction may take place
    cause otherwise chemistry is way above my head because I can't determine any patterns here.
    I don't know why we don't have a comprehensive list of reactions in 2018.

  • @dylanjackson7325
    @dylanjackson7325 Рік тому

    why the nitric acid + zinc go blue in the left jar???

    • @TheMrbunGee
      @TheMrbunGee  Рік тому

      You mean after 10 minute mark? Then it was copper, not zinc,

  • @aameenfathima4508
    @aameenfathima4508 6 років тому

    Which water you are adding In this

  • @aameenfathima4508
    @aameenfathima4508 6 років тому

    Sir please upload the full video

  • @Mylitla
    @Mylitla 9 років тому

    What? No audio.

    • @TheMrbunGee
      @TheMrbunGee  9 років тому

      +Mylitla English is not my main language, I am not good enough, to dictate my actions, sorry.

    • @l.wheels3458
      @l.wheels3458 8 років тому +1

      You could re release the video in you native language.

    • @l.wheels3458
      @l.wheels3458 8 років тому

      You could re release the video in you native language.

    • @TheMrbunGee
      @TheMrbunGee  8 років тому +3

      Logan Wheeler
      My native is latvian, less than 2 bilion people lives here of which only about 61% speaks latvian, + chemistry is not the priority interests here, so I don't think it is worth it. And major part of people who are interested in chemistry here know english language, so these demonstrations rearc more interested individuals if it is in english! :)
      I know myself, thats it is not as relaxing if you have to read whats happaning, I'll try to speak as soon as I feel ready! :)
      Thank you!

    • @l.wheels3458
      @l.wheels3458 8 років тому

      Ok.

  • @bharatnaiya2130
    @bharatnaiya2130 3 роки тому

    Copper tezabi bana shate he

  • @darquisraquelmoralesmonsal2863
    @darquisraquelmoralesmonsal2863 4 роки тому

    Alguien habla español ?

    • @TheMrbunGee
      @TheMrbunGee  4 роки тому +1

      Well everyone have google translate. :D
      [Todos tienen traductor de google.]

  • @UmardarazUmardaraz-po9uw
    @UmardarazUmardaraz-po9uw 4 роки тому

    Sir.please.tok.to.hindi

  • @danvandertorre9280
    @danvandertorre9280 6 років тому +1

    way too much talking

  • @khan9850
    @khan9850 7 років тому

    मो रिजवान खांन

    • @TheMrbunGee
      @TheMrbunGee  7 років тому

      Did You mean : मो रिजवान खान ?

    • @imprasad7721
      @imprasad7721 3 роки тому

      @@TheMrbunGee he is just telling his name😁

    • @TheMrbunGee
      @TheMrbunGee  3 роки тому

      @@imprasad7721 खांन , खान - what does the dot on top change?

  • @aameenfathima4508
    @aameenfathima4508 6 років тому

    Which water you are adding In this