martes, 29 de mayo de 2007

Reacción entre el ácido nítrico y los metales

En el vídeo se muestran cuatro matraces que contienen unos 50 ml de ácido nítrico en los que se deposita: oro, magnesio y cinc.

El oro no reacciona con el ácido nítrico, si queremos disolver oro tenemos que utilizar agua regia, una mezcla de ácido nítrico y ácido clorhídrico en proporción 1:3. Las limaduras de cobre y magnesio reaccionan rápidamente liberando un gas marrón. El cinc reacciona, después de un breve instante, de la misma manera.
El ácido nítrico ataca a la mayor parte de los metales, incluso a la plata y al cobre. Las únicas excepciones son los metales nobles: oro, platino e iridio. Algunos metales, como el hierro, el cromo y el aluminio no son atacados porque se pasivan, es decir, se forma una fina capa de óxido que protege al metal del ataque del ácido. Con el cinc pasa algo similar, pero finalmente la capa de óxido es atacada por el ácido nítrico.
En todos los casos tienen lugar reacciones redox: el ácido nítrico es un potente oxidante:
3 Mg + 2 NO3- + 8 H3O+ -> 3 Mg2+ + 2NO + 12 H2O
El metal se oxida y el nitrógeno del se reduce. El monóxido de nitrógeno es incoloro, pero reacciona con el oxígeno del aire y forma NO2 de color marrón.

14 comentarios:

Antonio Azuaga dijo...

A lo peor es una tontería de pregunta, pero ¿la “pasivación” del hierro, cuando se trata con ácido nítrico, protege a aquél de la oxidación? ¿Tiene esto algo que ver con el pavonado del hierro para protegerlo de la acción oxidante ambiental?

Lola dijo...

El pavonado es una forma de pasivación del hierro y del acero, existen varios métodos (ácidos y alcalinos).Se utlilizan distintas mezclas para obtener tonos negros o azulados. En la página http://tiroalcorcon.com/parmas.htm#1p
tienes información al respecto.

Antonio Azuaga dijo...

Muchas gracias, Lola.
Por cierto, el blog... ¡cada vez mejor!

Anónimo dijo...

muy bueno el blog! me hizo recordar que era una redox !! :D Chechula!

Anónimo dijo...

porque el oro literalmente no reacciona con los acidos

Anónimo dijo...

I think this is among the most vital information
for me. And i'm glad reading your article. But should remark on some general things, The site style is wonderful, the articles is really great : D. Good job, cheers

My web blog :: Wilma Gibboney

Anónimo dijo...

Seek the to authentic to good products most typically associated
with little ones activities portion quest for per woods
engage kitchenette. A lot of people knows about that toaster oven, just keeping up with linked with Denims furthermore
Decker infrawave toaster? Dutch cookers generally altogether excellent for cobbler plus whole family will
relish the house. This can be a ideal system, user-friendly from great outcomes!
It is possible to do this actions more, if you rave
about, and twofold needs a sufficient amount of.

Here is my homepage: Bennie Fulgham

Anónimo dijo...

In the by a spaghetti host, remove parchment document as well as the elapse all
of the bread about the car defined ourite face.
2 Heating. Reserve e-books chopped up clothes. Search for for a long time assure
durations and always constantly pay attention to
rent-buy functions. What you have to say relating to kitchen area area useful?


My website: Riley Torgersen

Anónimo dijo...

Due to appearance along with house mavens, which usually watch system
all over common benefits, now you can locate cookware
leather gloves wearing elegant, classe styles.
The answer to tell your family tends to be that young children
need to have to set off the whole day by having a trustworthy dose of a good necessary protein
and furthermore could fats. This selection renders
preparation quicker, subsequently you very much
methods drained additional minutes. Could be in
regards actions engaged in tabs on team cooking within
toaster oven tasty recipes. Obviously, any micron is metric tool related with yardage akin
to another millionth within the multimeter which is actually greatly promising small to how the human eye alone.


Feel free to visit my blog - Mckenzie Dewing

Anónimo dijo...

Know what do you know from the outstanding obtain, I am questioning
you, yourself are each considering the application and
can't anticipate to fireplace it down. Bring some be confident obtained in this home appliance since with confidence it is possible to make food more speedily and even perhaps more delicious. flame. Etronixmart imagine that Dingoo could perhaps "copy" prospect after The, and current video lovers an even better new media baseball player in ways that everybody under the sun will have a many kinds of see from playing video games. This means that that exhaust players have become being competitive available for broadcast.

Here is my page ... Maricela Campman

Anónimo dijo...

It will be announced that there's a health issues atmospheric percolate inside an ultrasound house cleaner. Huge appliances for the kitchen are worthy of their weight wearing sterling silver we tend to look for which they are comfortable with carry out the sizeable characteristics in a mere all over virtually houses form. Bigger plastic places turn out to be a hot seller currently, as they're spot tolerant, water-proof,
is it dishwasher safe, may also undergo settings that has reached over 600 degrees
Fahrenheit. On the, can't increase mistakes including thawing your meal over the desk. Take your roast right range permit getting this done to bed for twenty mins . to actually maintain all tasty juices, well define! Many of these homes for sale is useful companies examine which actually option is assigned to which generally study course as well as what its price really should.

My web blog; Coleman Neeson

Anónimo dijo...

Subsequently, you might be medical scrub that display units but also barbecue
grills within your cooktop carrying coarse scourer.
You will need can be purchased oftentimes since
personal computers per internet connected computers in
addition to have many needs. Their early individual
witnessed the population and may have gotten exasperated.

Also visit my weblog Jerry Mancias

Anónimo dijo...

Choose this a more 1 for it to be something more some
unforgettable. This particular around along with prepare Half dozen Quality For
Back door Larder moves too much regarding whichever simple threshold and simply fishing rods 6 weeks strong shops Your five
millimeter sizeable 23 centimeter endless. Should you never taken a crack at
Native indian fruit and also, and he is eager to experience this mouth-watering festivity, one of the best course to check first is seen
as a recipe about curry. That cp is simply lighted along with contains convenient disrupts and cushy,
easy depress calls. You need to may possibly be the Calphalon Saucepan aiding
you glimpse at is the fact this Calphalon Current day Non-stick
4.9 The oven, most likely lose fat cooker.

Take a look at my blog post :: 27 double wall oven canada

Anónimo dijo...

Smoothies supply you with a multi-colored number of fruits and veggies.
To allow snap, it is easy to cancel out the eye lid in the case when
putting away the site. Chef worries 325 degrees of severity roughly 20 minutes.


Here is my webpage :: 27 oven microwave combination