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Showing posts with label ISOMERISM:. Show all posts
Showing posts with label ISOMERISM:. Show all posts

Sunday, May 22, 2022

Write all the the chain and positional isomers of Heptane and also write their IUPAC name.


Number of chain and postional isomers alkane and number of respective carbon atoms present.

Write the total Isomers of 1,1-Dicloro propene (C3H4Cl2)?.





Number of structural isomers monoclorinated alkane and number of carbon atoms present.

Related Questions:







Write the total Isomers of 1,1-Dicloro propene (C3H4Cl2)?.

How determination of chirality in Meso compounds ?

Identifying planes of symmetry in Fischer formulas is relatively easy, since they are planar representations.
The following illustrations show examples of both chiral and achiral molecules.
The process of assigning absolute configurations to the chiral centers in molecules containing two or more of them is basically an extension of the process followed for molecules containing only one. However, it helps to isolate the chiral centers and deal with one at a time to avoid confusion.
The following example illustrates this point. In this example we have numbered the carbon atoms in the
main chain according to IUPAC rules that will be studied later.
We have also marked the chiral carbons with asterisks.
Once the chiral centers have been identified, we focus on one at a time (shown as a red dot). First, we isolate carbon-2, then we assign priorities to the groups bonded to it, and assign configuration. In this case the configuration of carbon-2 turns out to be (R). A similar process for carbon-3 also leads to (R) configuration.
The IUPAC notation used to indicate the configurations at carbons 2 and 3 is therefore (2R, 3R).

Related Questions:








The term stereogenic center or stereocenter:

A stereogenic center is defined as an atom on which an interchange of any two atoms or groups result in a new stereoisomer, When the new stereoisomers is an enantiomer ,the stereocenter is called chiral center. All stereocenters are not tetrahedral.
First and second are enantiomers (non superimposible mirror images), Hence the steriocentre is a chiral centre.
III and IV are not enantiomers. they are diasteriomers hence in this case sterio centres are not chiral centres. Also these are not tetrahedral. Thus, all chiral centres are sterio centres but all steriocentres are not chiral centres. If a molecule contains only one chiral centres it must be chiral. Molecule containing two or more 
chiral centres may or may not be chiral. For example: meso tartaric acid has two chiral centres but it is achiral.


The term Asymmetric center and chiral center :

Three terms are used to designate, a carbon atom bonded tetrahedrally to four different substituents in a chiral molecule: 
Asymmetric atom, chiral center or stereocenter.
Let us understand chiral and achiral center taking few more examples.
Related Questions:








Tuesday, June 23, 2020

How do you calculate the number of all possible structural isomers for alkanes?

Yes we can find all possible structural isomers Of a given hydrocarbon.

Number of total structural isomers = 2^(N-4)+1

Where N is number of carbons in hydrocarbon

Example: (1)
Number of structural somers of butane (C4H10) is 

SOLUTION:

Where , n=4
=2^(4-4)+1
=2^(0)+1
=1+1
=2

Example: (2)
Number of structural somers of butane (C5H12) is.

SOLUTION:

Where , n=5
=2^(5-4)+1
=2^(1)+1
=2+1
=3

Example: (3)
Number of structural somers of butane (C6H14) is.

SOLUTION:

Where , n=6
=2^(6-4)+1
=2^(2)+1
=4+1
=5

Example: (4)
Number of structural somers of butane (C7H16) is.

SOLUTION:

Where , n=7
=2^(7-4)+1
=2^(3)+1
=8+1
=9

Example: (5)
Number of structural somers of butane (C8H18) is.

SOLUTION:

Where , n=8
=2^(8-4)+1
=2^(4)+1
=16+1
=17

Example: (5)
Number of structural somers of butane (C8H18) is.

SOLUTION:

Where , n=9
=2^(9-4)+1
=2^(5)+1
=32+1
=33


How to find number of stereoisomers in a large compound (polyenes) containing double bonds?

Number of stereoisomer of polyenes can calculated by following formulas .

How to find number of stereoisomers in a large compound containing chiral centres ?.

Wednesday, January 29, 2020

Write total fuctional isomers of molecular formula C5H10O.

Total fuctional isomers of molecular formula C5H10O Possible are six which are given as:

Friday, January 24, 2020

Although anti conformation is more stable than the gauch conformation but in some cases gauch or skew conformation is more stable than the anti confirmation why?

Gauch or skew conformation is more stable than the anti because of the intramolecular hydrogen bonding which is geometrically possible only in the gauch conformation.
For examples:
Ethane-1,2-diol, 2-Fluoroethan-1-ol, 2-chloroethan-1-ol and 2-Aminoethanol etc.
2-chloroethane-1-ol:
Ethane-1,2-diol:

What is Imine-Enamine tautomerism?

An imine is a compound that contains a -C=NH bond. It is homologous of -C=O. And Imime form is just similar to keto form and Enamine form is just similar to Enol form . The Imine-Enamine tautomerism is due to the migration of alpha hydrogen from one polyvalent atom to another to form Enamine thus Imines can be converted into enamines.

Realated Questions:

Thursday, January 2, 2020

How many different structural isomers exist with the formula C5H10? (Except geometric and optical isomers) :


(A) There are five linear Isomers:
(1) Pent-1-ene (2) Pent-2-ene (3) 2-Methylbut-1-ene (4) 2-Methylbut-2-ene (5) 3-Methylbut-1-ene


(B) There are five cyclic Isomers:

(1) Cyclopentane (2) 1-Methylcyclobutane (3) 1-Ethylcyclopropane (4) 1,1-Dimethylcycloprone (5) 1,2-Dimethylcyclopropane



Wednesday, January 1, 2020

How many cyclic isomers possible of (C6H12) Hexene?

There is twelve cyclic compounds can draw with molecular formula of (C6H12 ) hexene. Six – Four member cyclic compounds and six - three member cyclic compounds  
(A) Six – Four member cyclic compounds:
(1) Cyclohexane (2) 1-Methylcyclopentane (3) 1-Ethylcyclobutane (4) 1,1-Dimethylbutane (5) 1,2-Dimethylcyclobutane (6) 1,3-Dimethylcyclobutane

(B) Six - three member cyclic compounds:
(1) 1-Propylcyclopropane (2) 1-(1-methylethyl)cyclopropane (3) 1-Ethyl-1-methylcyclopropane (4) 1-Ehtyl-3-methylcyclopropane (5) 1,1-Dimthyl-2-methylcyclopropane (6) 1,2,3-Trimethylcyclopropane.

How many cyclic isomers possible of (C5H10) pentene?

How many cyclic isomers possible of (C5H10) pentene?

There is five cyclic compounds can draw with molecular formula of (C5H10 ) Pentene.
(1)  Cyclopentane (2) 1-Methylcyclobutane (3) 1-Ethylcyclopropane (4) 1,1-Dimethylcycloprone (5) 1,2-Dimethylcyclopropane