Some of the additive questions in high school chemistry are answered

Hydrogen on lipid and carboxyl groups cannot be added because one carbon with two hydroxyl groups is unstable. The aldehyde group is added to the hydroxyl group, and the ketone tan (that word can't be typed) group seems to be not, at least not in high school chemistry. Only the phenolic hydroxyl group replaces the halogen atom and cannot be reversed.

The halogen atom cannot break the unsaturated bond in the benzene ring. For the same carbon-carbon double bond, there will be two halogen atoms when replaced by halogen element, and one hydrogen atom and one halogen atom when replaced by hydrogen halide.

In fact, the lipid group, carbonyl group, aldehyde group, and carboxyl group can all undergo hydrogenation reaction, but this is within the scope of the university, and the high school stage indicates that the carbonyl group is difficult to add, and the addition of the carbonyl group is a special addition reaction, and the university can learn that the saturated hydroxyl group on the benzene ring can be replaced with halogen elements under light conditions, which can be regarded as a substitution with alkanes

The double bond in the benzene ring only adds to hydrogen, and halogen element, or nitrate sulfuric acid will only be substituted under certain conditions, there are many questions about addition and substitution in the title, the fundamental difference between the two you said is only the difficulty of this reaction is different, halogen elements are more likely to occur substitution and addition, for example, there are no special conditions for the addition of bromine water and ethylene, while the addition of hydrogen bromide requires a catalyst.

Over, if you don't understand, you can ask me, hope

Functional groups that can have addition reactions: carbon-carbon double bond, carbon-carbon triple bond, carbon-oxygen double bond, carbon-nitrogen triple bond, benzene ring. You have all these high school textbooks, look for them yourself!

As follows:

The 1,2 addition is the breaking of a double bond and the addition of another atom or group to each of the two c atoms at the 1st and 2nd positions. For example, isoprene has two double bonds, which can produce two 1,2 adducts.

The 1,4 addition is when both double bonds are broken, and one other atom or group is added to each of the two c atoms at the 1st and 4th positions to form a new double bond between the 2nd and 3rd c atoms. For example, isoprene can generate 1,4 adducts.

High school chemistry is a relatively independent research system in the field of chemistry, and the main research personnel include high school students and high school teachers in China.

High school chemistry is a chemical system that has been transformed to adapt to high school teaching and reduce the burden on students, while avoiding some complex but often intrinsically powerful theories or facts. It is often quite different from the actual field of chemistry, and there may be some substances that do not actually exist (such as ammonium hydride), but they are uniformly used in the test questions at the high school level. It has a great support staff (including most of the high school students and most of the high school teachers) and a great influence.

For example, there are 4 carbon atoms arranged in a row, numbered 12341 and 2 in order, and there is a double bond between 3 and 4, such as butadiene.

Under certain circumstances, the double bond between 1,2 of butadiene will open, and other things will be added to the carbon atoms 1 and 2, which is the 1,2 addition.

And if both double bonds are broken, then a new carbon-carbon double bond will be formed between the 2,3 carbon atoms, and at this time something new will be added to the 1,4 carbon, which is called the 1,4 addition.

The addition of olefins and hydrogen forms alkanes, the addition of alkynes to hydrogen to form alkenes or alkanes, the addition of aldehydes and ketones to hydrogen to form alcohols, and the addition of benzene to hydrogen to form cyclohexane.

Olefins are added to halogens to form o-dihalogenated hydrocarbons, alkynes are added to halogens to form haloalkenes or haloalkanes, and benzene is added to chlorine to form hexachlorocyclohexane.

Olefins are added to hydrogen halides to form halogenated hydrocarbons, alkynes are added to hydrogen halides to form halogenated olefins or halated alkanes are added to water to form alcohols, alkynes are added to water to form aldehydes or ketones, and aldehydes or ketones are added to hydrocyanic acid to form hydroxynitrile.

Additions: olefins,

Alkyne. with hydrogen, bromine, water,

Hydrogen halide. bonus.

Benzene. Addition to hydrogen.

Carbonyl, aldehyde group.

Addition (reduction) with hydrogen

Hydrogenation (hardening) of fats and oils is also an addition.

Some hydroreduction is also available.

Addition reaction. Substitution: hydrocarbons with halogens.

Substitution reactions. Including benzene ring and benzene ring.

Sidechains. Substitution reaction of alcohols with hydrogen halides.

Alcohols. Intermolecular dehydration.

The reaction of the ether also belongs to substitution.

Esterify. It also belongs to substitution.

Addition is the addition of multiple substances into one, strictly following the principle of many change one. Example.

Olefins or alkynes can only be additioned.

Substitution is the formation of two new compounds formed by the breaking of a part of an organic substance and the exchange of their respective parts with another substance that has broken the chemical bond. The principle is similar to that of displacement in inorganic reactions. Both the reactant and the product are two. Example.

Alkanes can only be substituted.

NH4+ ions are to be hydrolyzed, NH4+

h2o<===>

Whereas, Mg can react with H+ to form Mg2+

and H2 to reduce the concentration of the product H+ and promote the further hydrolysis of NH4+.

Why is magnesium hydroxide precipitated not generated, this is because in the process of reaction, whether Mg2+ precipitates in the form of magnesium hydroxide depends on the pH value of the solution, the beginning of the reaction solution is acidic, and there is no possibility of Mg(OH)2 Even in the end, because the Mg2+ and concentration in the solution are not large, it is not enough to reach the pH of the formation of Mg(OH)2 precipitate (the pH of magnesium hydroxide precipitate is higher).

From another point of view, magnesium hydroxide is a moderately strong alkali, which is stronger than the weak alkali ammonia, mg(OH)2+

2nh4cl

==>mgcl2+

Magnesium hydroxide is soluble in ammonium chloride).

Therefore, in order to precipitate magnesium hydroxide, the solution must be alkaline (concentrated ammonia condition).

Addition: Addition of olefins, alkynes and hydrogen, bromine, water, hydrogen halide Addition of benzene ring and hydrogen.

Addition (reduction) of carbonyl groups, aldehyde groups and hydrogen

Hydrogenation (hardening) of fats and oils is also an addition.

Some hydroreduction is also an addition reaction.

Substitution: substitution of hydrocarbons with halogens (including benzene ring and benzene ring side chains) and substitution reaction of alcohols with hydrogen halides.

The reaction of dehydration of alcohols into ethers between molecules also belongs to substitution.

Esterification also falls under substitution.