How do we determine whether a molecule is exhibiting +R effect or -R effect(positive mesomeric effect or negative mesomeric effect)?
Answers
Hola mate
Here is your answer -
Well, let's start with the basics. In chemistry, two compounds are said to be distinct even if there is a slight difference in their structures. For example, a structure of benzene , kept in front of a mirror would account for another structure (though it may appear the same). This is what we call as resonance.
Beginning with your question now, I am a student myself and explaining what my Professor has taught me.
As I said above, different forms of the same structures are distinct.
So the first step is to draw the Lewis structure of the compound, which you want to identify, whether resonates or not.
After drawing the structure, look out for the "double" bonds.
Now these bonds may occur in the following series with respect to the double bond:
A double bond, followed by a single bond and something else ahead(would elaborate ahead, again)
A double bond followed by another double bond and so on.
Now, considering the first case, resonance occurs in the follochargesub cases:
When the double is followed by a single bond, followed by another double bond or
- ""..followed by a triple bond
- "".. Is followed by positive charge
- "".. Is followed by a negative charge
- "".. Is followed by a free radical
A triple bond followed by a single bond and followed by a double bond.
In the second case, that is where the double bonds are present consecutively (one after the other), resonance occurs.
Now to find the resonance structures, you have to consider such sequences of bonds and charge.
Blaise here..
that's not alov in the dp...
lol xd