Acid+salt = new acid+new salt reaction conditions: only when gas or water or precipitation is generated can the reaction type be decomposed. Example: 2HCL (acid) +Na2CO3 (salt) = H2CO3 (new acid) +2NaCl (new salt).
However, carbonic acid is unstable: H2CO3=H2O+CO2↑ thus gas and water are formed.
Acid+active metal = salt+hydrogen reaction conditions: metal is active metal reaction type: replacement
For example: 2HCl (hydrochloric acid) +Fe (active metal) = FeCl2 (salt)+H2 = (hydrogen).
Acid+metal oxide = salt+water reaction conditions: no reaction type: double decomposition.
Example: H2SO4 (acid) +CuO (metal oxide) = CuSO4 (salt) +H2O (water) [Edit this paragraph] The nature of alkali+acid-(see the nature of acid).
Alkali+salt = new alkali+new salt reaction conditions: both alkali and salt must be soluble in water and precipitate (both meet).
Reaction type: double decomposition reaction conditions: precipitation, water or gas are generated in the reaction.
Example: Ca(OH)2 (alkali) +K2CO3 (salt) = CaCO3↓ (new salt) +2KOH (new alkali)
Alkali+part of nonmetallic oxide = salt+water reaction conditions: nonmetallic oxide is acidic oxide reaction type: double decomposition.
Example: Ca(OH)2 (alkali) +CO2 (nonmetallic oxide) = CaCO3↓ (salt) +H2O (water)
This reaction is used to identify the properties of CO2 salt [edit this paragraph] salt+acid-(see properties of acid).
Salt+alkali-(see the nature of alkali)
Salt+salt = new salt+new salt reaction conditions: all salts must be dissolved in water, and there is precipitation in the product (both are satisfied).
Reaction type: double decomposition
For example: BaCl2+Na2So4=BaSo4↓+2NaCl.
This is a precipitation reaction.
Salt+partial metal = new salt+new metal reaction conditions: salt can be dissolved in water, and the activity of metal is greater than that in salt (both are satisfied). Reaction type: displacement.
For example: CuSO4 (salt) +Fe (metal) =FeSO4 (new salt) +Cu (new metal)
But some metals cannot achieve this reaction, except potassium, calcium and sodium, because they react with water.
Acid oxide:
A substance (usually a nonmetallic oxide) that is acidic when dissolved in water.
CO2 (carbon dioxide) is carbonic acid after being dissolved in water, and carbonic acid is acidic, so CO2 is an acidic oxide.
Basic oxide:
Similar to the above, it is an alkaline substance (usually a metal oxide) after hydration.
After CaO (calcium oxide) is dissolved in water, the solution is alkaline. Therefore, CaO (calcium oxide) is the reaction property of basic oxides about acid, alkali and salt. Know what is soluble and what is insoluble.
Then there is a formula:
Soluble potassium nitrate, sodium nitrate and ammonium nitrate mean that nitrate, potassium salt, sodium salt and ammonium salt are all soluble in water.
Carbonic acid has no trivalent salt, that is, it is generally believed that metal ions in carbonate have no trivalent salt.
Removing silver and mercury with hydrochloric acid means that the chloride of silver and mercury is insoluble in water.
Barium sulfate and lead sulfate mean that they are insoluble in water.
There are five positions in the alkali solution. .......
Potassium, sodium, ammonium, calcium and barium mean (last sentence): Generally, only five kinds of alkali can be dissolved in water: potassium, sodium, ammonium, calcium and barium (calcium is slightly soluble).