chemical reaction with the metal acid is specific for these classes of compounds.In the course of its proton and hydrogen is recovered in conjunction with the acid anion is replaced by a metal cation.This is an example of the reaction to form the salt, although there are several types of interactions do not obey this principle.They occur as redox and not accompanied by the release of hydrogen.
Reaction Principles acids with metals
All reactions inorganic acid leads to the formation of metal salts.The exception is, perhaps, only the reaction of the noble metal with aqua regia, a mixture of hydrochloric and nitric acid.Any other interaction of acids with metals leads to the formation of salt.If the acid is neither concentrated sulfuric or nitric acid, the product cleaved as molecular hydrogen.
But when reacting concentrated sulfuric acid, the reaction proceeds with metals according to the principle of the redox process.Because it was experimentally identified two types of metals and interactions typical of strong inorganic acids:
- the interaction of metals with dilute acids;
- interaction with concentrated acid.
reactions of the first type occur with any acid.The only exception is concentrated sulfuric acid and nitric acid any concentration.They respond to a second type and lead to the formation of salts, reduction products of sulfur and nitrogen.
Typical acids reacting with metals
metal located left of hydrogen in a standard electrochemical series are reacted with dilute sulfuric acid and other acids of different concentrations except nitrogen to form a salt and isolating the molecular hydrogen.Metals are located right in the series hydrogen electronegativity can not react with the above mentioned acids and interact only with nitric acid regardless of concentration, with concentrated sulfuric acid and aqua regia.This is a typical reaction of an acid with metals.
metal reactions with concentrated sulfuric acid
When the content of sulfuric acid in solution more than 68%, it is considered concentrated and reacted with the metal left and right of hydrogen.The principle of the reaction with metals of different activities is shown in the photo below.Here, the oxidizing agent is sulfur into sulfate anion.It is reduced to hydrogen sulfide, 4-valence oxide or to molecular sulfur.
reactions with dilute nitric acid
dilute nitric acid reacts with metals located to the left and to the right of hydrogen.During the reaction with the active metals to produce ammonia, which immediately dissolves and reacts with the nitrate anion to form another salt.With metals average activity of the acid reacts with the release of molecular nitrogen.With less active reaction takes place with the release of 2-valence oxide of nitrogen.In most cases, several forms of sulfur reduction products in a single reaction.Examples of reactions proposed in a graphics application below.
Reacts with concentrated nitric acid
In this case, an oxidizing agent also acts as nitrogen.All reactions were run out salt formation and release of nitric oxide.Schemes of redox reactions proposed for graphics application.This reaction deserves special attention of aqua regia with less active elements.Such interaction of acids with metals nonspecific.
metals Metals react with acids quite willingly, though there are more inert substances.This precious metals and elements having a high standard electrochemical potential.There are a number of metals, which is built on the basis of this indicator.It is called the electronegativity.If the metal is placed therein to the left of the hydrogen, it can react with dilute acid.
There is only one exception: iron and aluminum due to the formation on the surface of 3-valence oxides can not react with the acid without heating.If the mixture is heated, it initially reacting a metal oxide film, and then it is dissolved in the acid itself.Metals are located to the right of hydrogen in the electrochemical series activity can not react with an inorganic acid, including sulfuric and dilute.Two exceptions to the rule: these metals are dissolved in concentrated and dilute nitric acid and aqua regia.The latter can be dissolved only rhodium, ruthenium, iridium and osmium.