Acid and Metal Reactions

A. Some acids react with some metals and not all acids react with all metals. It all depends on what is reacting with what. However, assuming there is a reaction, the acid will dissolve the metal to produce the metal salt of that acid; at the same time it will produce hydrogen gas. i.e., 2H⁺ + M = 2M⁺ + H₂

However, there are some exceptions; if you mix conc. nitric acid with copper, you will get clouds of brown nitrogen dioxide gas.

A. Thanks, Trevor.

As you know, there is a reason for that special reaction between nitric acid and copper, but it doesn't exactly have to do with metals and acids. HNO3 doesn't just ionize into H+ as a cation and NO3- as a stable anionic radical per your equation, like other acids -- rather, the NO3 acts as a very powerful oxidizing agent.

Although we call it nitric acid, it probably could have been called "nitric oxidizing agent" :-)

Regards,

A. It would be a chemical reaction.

A. When acids and metals react, a salt and hydrogen is produced

A. Hi, Bradley. I'd say that most of the time nothing would happen because the metal has already reacted with oxygen to form a metal oxide and the reaction is done. Sort of like what happens when you burn ashes: nothing, the reaction is done.

But there could be some metal oxides like Cu₂O that might be further oxidized to CuO.

Regards,

"Hi, Bradley. I'd say that most of the time nothing would happen because the metal has already reacted with oxygen to form a metal oxide and the reaction is done. Sort of like what happens when you burn ashes: nothing, the reaction is done."

A. With all due respect, this is untrue. The reaction will proceed, but no gas will be evolved. Instead of a salt and hydrogen being produced, you will get salt and water.

The hydrogen from the acid will react with the oxygen from the oxide to form the water.

Hi, Ceri. Thanks. But ...

Although the title of the thread talks about acid reactions, and you are right that when an acid reacts with a metal oxide you will get a salt and water, Bradley asked about reacting a metal oxide with oxygen, not with acid. And that's the question I answered :-)

Regards,

A. Hi, Kala.

Aluminum plus hydrochloric acid reacts to produce aluminum chloride and hydrogen gas. The general idea, in formula, would be along the lines of:

Al + HCl => AlCl₃ + H₂^

But there is a problem with this "formula", in that it doesn't balance because there is not the same number of atoms of the three elements on each side of the equation. You need to have three HCl's on the left to provide the 3 Cl's in the AlCl3 on the right:

Al + 3HCl => AlCl₃ + 1.5H₂^

But there is still a problem because there is no such thing as one and a half molecules of hydrogen gas. So the actual formula is:

2Al + 6HCl => 2AlCl₃ + 3H₂^

Regards,

A. Hi, Rekha. Your question is not so much a question in the sense of "you know the answer or you don't", as an assignment for the student to think about. It seems to me that if we claim that hydrogen gas is produced, we should:

First, see if any gas was produced. What did your experiment reveal? Did it or did it not generate gas?

Second, capture that gas in a bottle. This could be done by sinking the bottle into the water and removing any air, then positioning the bottle to capture the rising gasses.

Third, test if the gas that was captured is hydrogen. This you would do by comparing some of the properties of the captured gas to the properties of hydrogen. Good luck.

Regards,

A. The test for hydrogen gas is to put a lit splint into the bottle filled with gas captured from the experiment. If you see a small pop around the lit area of the splint, or hear a 'squeaky pop' sound, then the gas is probably hydrogen.

A. Hi, Romel.

G.I. means galvanized iron (more likely to actually be galvanized steel). Galvanized means coated with zinc.

The zinc will almost instantly dissolve in hydrochloric acid.

Regards,

A. Hi, Joan. You should probably sprinkle baking soda [in bulk on eBay or Amazon [affil links] (a lot of it) there to neutralize the acid remnants. Dabbing it up, you didn't get it all.

Regards,

A. Hi Malachy. Let me ask you a question first: How much is 351 plus 426? I am confident that you can do this in your head, and equally confident that no teacher ever presented that particular pair of numbers to you. The point is that you learned "extensible" lessons in arithmetic class, like adding the ones column, the tens column, and the hundreds column, rather than learning the sums of pairs of large numbers by rote.

Although the question you have asked seems a bit advanced for a 12 year old, I'm confident that the point is not for him to simply memorize a meaningless list of 7 metals by rote, but to learn something "extensible" about chemistry, like the general idea of rows and columns of "The Periodic Table". Thus I suggest that he google that term and, combining it with what he can read on this page, i.e., that aluminum and zinc are two of those metals, he should be able to make some excellent guesses towards 5 more metals, and then look up the metals he guesses at to confirm the reaction. Best of luck!

Regards,

A. Hi, Naveen.

Your question unfortunately entangles issues of practicality, theory, and semantics :-)

Semantically, there is no possible way to avoid formation of metal salts, because we are talking "definitions", and the reaction product of metals and acids metallic salts is "defined" as hydrogen plus metallic salts. But speaking in terms of theory, these salts do not necessarily precipitate, they may remain in solution depending on their solubility limit at a given temperature. In practical terms, you can certainly filter out any non-soluble metal salts and the remnants of the reaction between paint and acid. Good luck.

Regards,

A. Another 'solution' would be for Naveen to make all of his / her labware and lab furniture out of acid-resistant plastics! No metal salts there!

(Sorry, I couldn't resist...)

A. Hi, Naay. Are you asking what would happen if you combined an acid like HCl with a carbonate like CaCO3?

_H⁺Cl^- + _Ca⁺⁺CO₃^{- -} =>  ?

Balance the equation and write your guess, and then we can go on ...

Regards,

A. Hi. One example is that metals are dissolved in acids so that we can electroplate them; for example to make relatively inexpensive jewelry out of copper, but coated with gold. Acids are also used to remove rust from steel and tarnish from other metals. Wet a cloth with vinegar ⇦in bulk on eBay or Amazon [affil links] (an acid), shake a little salt on it, and rub the tarnish off a brown penny with it.

Regards,

A. Hi Megan. Please put this into context. Otherwise, people might assume that you simply posted your homework assignment on the internet for someone else to do :-)

But start by considering what reactions might occur with these reagents, and what observable properties the products of the reaction might have. Good luck.

Regards,

Thanks for the advice. Anyway I've found the answer. A white precipitate, Barium sulphate, BaSO4, will be formed.

Congratulations, Megan!

As a "BTW" which you might want to add to your report, to do chrome electroplating the plating shops need to use a mixture of almost precisely one part sulfuric acid per 100 parts of chromic acid. For reasons that almost nobody really understands, too little sulphate and you cannot plate chrome from it; too much sulphate and you cannot plate chrome from it either.

Guess what electroplating shops do to their chrome plating tanks if they have too much sulphate? They add barium to precipitate the excess sulphate per this poem .

Regards,

A. Dear Zoey,

sulfur (only S atoms) is a non-polar solid that does not react with acids, at least at room temperature (with nitric acid you may get a reaction heating, but I don't think that you could with hydrochloric). So, you may get some sulfur and hydrochloric acid as products (no change).

Zinc (Zn atoms in a crystalline metal matrix) is a metal that DOES react with acids eagerly... You may get hydrogen and zinc ions (Zn++) as byproducts in this reaction:

2 HCl + Zn --> H2 + Zn++ + 2 Cl-

Hope I answered your question! Best regards,

A. Hi Zoey,

Probably too late for you to use, but the first thing you should do is write the left hand side of the chemical equations:

e.g. Zn + HCl -> ?
S + HCl -> ?

Now if you can work out what goes on the right hand side of the equation and balance up all your atoms it should give you an idea whether you will witness anything happening or whether it will just sit there and not react at all. Best of luck.