Combination reaction: refers to the reaction of two or more substances forming new substances. Among them, some of the four basic reaction types are redox reactions and some are non-redox reactions. In addition, chemical reactions generally release energy.
Decomposition reaction: Decomposition reaction is one of the common types of chemical reaction, and it is the reverse reaction of chemical combination reaction. A reaction in which a compound is decomposed into two or more simple substances or compounds.
Displacement reaction: Displacement reaction is a chemical reaction in which a simple substance reacts with a compound to generate other simple substances and compounds. It is one of the four basic reaction types in chemistry, including the reaction between metals and metal salts, and the reaction between metals and acids.
Double decomposition reaction: Double decomposition reaction is a reaction in which two compounds exchange components with each other to form two other compounds. Its essence is that the two substances that undergo metathesis reaction exchange ions with each other in aqueous solution and combine to form a substance that is difficult to ionize-precipitation.
deposit
Gas and water reduce the ion concentration in the solution, and the chemical reaction proceeds in the direction of ion concentration reduction. It can be abbreviated as ab+CD = ad+CB.
To judge whether a reaction is a combination reaction, we should focus on the concept and characteristics of the combination reaction. If we want to judge whether a reaction chemical equation belongs to a combination reaction, we should take this reaction as the premise and then compare it with all the characteristics of the combination reaction. Only by having three reaction characteristics at the same time can it be determined as a combined reaction. Otherwise, it cannot be included in the combination reaction.
To judge whether a reaction has undergone a double decomposition reaction, it must conform to the characteristics of the double decomposition reaction and the conditions under which the reaction occurs. Only when both are available, the metathesis reaction occurs.
The essence of the metathesis reaction is that the ions in the solution combine into substances that are difficult to ionize (such as water), insoluble substances or volatile gases, so that the metathesis reaction tends to be completed.
The reaction between acid, alkali and salt solution is generally formed by the exchange of components between the two compounds, that is, the compounds participating in the reaction ionize and dissociate into freely moving ions in aqueous solution, and the ions recombine into new compounds, so the reaction between acid, alkali and salt solution is generally a metathesis reaction. The metathesis reaction is the recombination of ions or ionic groups, because the valence of each element has not changed before and after this reaction, so the metathesis reaction is not a redox reaction.