In case of unsymmetrical alkenes the addition of hydrogen halide takes place according to the markovnikov’s rule . During this reaction under markovnikov’s rule the positive part of the attacking reagent joins with the carbon with more number of Hydrogen and the negative part of attacking reagent joins with the more substituted carbon.
Category Archives: chemistry
How we can make alkyl halides or haloalkanes from alkenes ?
We can make haloalkanes from the alkenes by treating them with rhe hydrogen halides HX . Here the double bond is converted into single bond , hydrogen and halogen gets attached to the carbons involved in double bond.
How we can prepare dibromoethane from ethene ?
We can make the dibromoethane from ethene by the addition of halogen in ethene , in the presence of carbon tetrachloride. In the presence of ether as a solvent the above reaction takes place. The dihalo products are formed in which the halogen groups are present on adjacent carbon atoms.
How we can prepare ethane (alkane) from ethene (alkene) ?
By catalytic hydrogenation we can get the alkanes from the alkenes. The reaction takes place by reacting ethene with hydrogen in the presence of platinum and pladium and Rany nickel (active form of Nickel) Here is the reaction :-
Mechanism for electrophillic addition reactions of alkenes
The mechanism involves the following steps :- Step 1 :- In first step the polarity is developed on the bromine molecule , and the partial positive side of the bromine molecule attacks on the carbon atom of the double bond. This leads to the formation of carbocation. Step 2 :- In second step the negativeContinue reading “Mechanism for electrophillic addition reactions of alkenes”
Why the alkenes give electrophillic addition reactions ?
Alkenes give electrophillic addition reactions because of the following reasons:- 1. The pie electrons of the double bond attract electrophiles . 2. The electron density is more on the C-C double bond , so the electrophiles preferably attack on it as compared to the electrophiles which are repelled.
How we can prepare alkene from dicarboxylic acids ? Kolbes’s electrolysis
In this reaction the decarboxylation of dicarboxylic acids take place . The potassium salts of dicarboxylic acid give alkene as the COO- group is removed as CO2 , this leads to the formation of double bond between two adjacent carbon atoms.
What is the mechanism of acidic dehydration of monohybrid alcohol ?
The complete mechanism takes place in three steps as shown below :- Step 1 :- Step 1 involves the release of Hydronium ion (proton) and then the attack of proton on the lone pair electrons of oxygen. By this way protonated alcohol is formed. Step 2 :- This step is slow and rate determining step.Continue reading “What is the mechanism of acidic dehydration of monohybrid alcohol ?”
How we can get ethene from ethanol ? What are the products of acidic dehydration of monohybrid alcohol ?
How we can get alkenes from gem-dihalides by dehalogenation ?
How we can prepare the alkenes from dihaloalkanes or vicinal dihalides ?
By just heating in the presence of methanol we can get the alkene by treating the vicinal dihalides with zinc. Here Is the complete reaction:-
What is beta elimination in dehydrohalogenation of alkyl halides ?
In these kind of reactions the Saytzeff rule is followed. Here is the reaction and its conditions:-
How we can prepare alkene from alkyl halides ?
We can obtain the alkenes from alkyl halides by the Dehydrohalogenation. In this kind of reaction the halogen and hydrogen from adjacent carbon are removed to make a double bond in the presence of alcohlic KOH . The reaction is shown below.
What is cracking or pyrolysis of alkanes ?
It is a kind of reaction in which under suitable conditions of temprature and pressure a simple alkane can give various products. As shown below. Pyro means the heat and lysis means the breaking, so it is a process of breaking the alkanes in the presence of heat.
What is birch reduction give its reaction ?
In this kind of reduction the alkynes are reduced with sodium in liquid ammonia. This leads to the formation of Trans alkenes.
How we can prepare But-2-ene(alkene) from But-2-yne (alkyne) by the partial reduction ?
By the partial reduction of alkynes we can obtain alkenes.
How we can make toluene from n-heptane ? Cyclisation of alkane
The alkane on treatment with chromium oxide , 773 kelvin temprature and 10 to 20 atmospheric pressure gives the aromatic compound. As in the following reaction we can get the toluene.
How we can do aromatisation in alkanes ? How n hexane can be converted into benzene ?
The aromatisation of alkanes can be carried out under rigorous conditions. N-hexane can be converted into benzene, under the high condition of pressure that is 10 to 20 atmospheric pressure and temprature nearly 773 kelvin. Firstly we will get cyclohexane, on further dehydrogenation we get the benzene as shown below.
How we can prepare 2-methylpropane or isobutane from Butane ? Or What are the isomerisation reactions shown by alkanes ?
The Alkanes show isomerisation reactions in which one isomer is converted to another isomer under certain conditions. We can convert the Butane into isobutane by treating it with Aluminium chloride and Hydrochloric acid at 573 kelvin temprature.
What are the products of the catalytic oxidation in alkanes.
The catalytic oxidation of alkanes leads to the formation of alcohols , aldehydes and carboxylic acids under various conditions . The detailed reactions are as follows :- 1. Prepration of alcohol on reaction with oxygen in the red hot copper tube. 2. Preparation of aldehyde This reaction takes place in the presence of Molybodinum trioxide.Continue reading “What are the products of the catalytic oxidation in alkanes.”
What are the oxidation reactions of Alkanes ?
The oxidation of alkanes is of two types 1 . Complete oxidation or combustion 2. Incomplete combustion 3. Reaction with steam 4. Catalytic oxidation These reactions can be seen in the given link
How does n- hexane alkane reacts with Sulphuric acid ?
The n-hexane or alkanes give the following reaction on reacting with Sulphuric acid. The above reaction is also known as the sulphonation of alkanes.
Mechanism of substitution reactions of Alkanes
This kind of reactions involve the formation of free radical intermediates. Following are the steps of mechanism :- Step 1 :- Chain initiation In this step the bond in halide molecule breaks by a homolytic cleavage . And this leads to the formation of free radicals. Step 2 :- Chain propagation In this step theContinue reading “Mechanism of substitution reactions of Alkanes”