if any nucleophille is given how can we say that it is weak or strong nucleophille?
21It has to be strong or weak Leaving Group respectively, i.e the conjugate Acid of the respective Nucleophile has to be Strong if the LG is strong..... Else if the Conjugate Acid is weak it would imply Strong Nucleophilicity....
Weak Conjugate Acid→ Less stable Counjugate Base of the acid→ Bad Leaving Group→ Good Nucleophile
The converse, Vice versa, Permutations and opposite of the above statement are all true...
7The strength of the nucleophile also depends largely on the nature of the substrate and the solvent.
11U have to see whether its a strong or a weak base...
stronger the base->stronger nucleophile
weaker the base->stronger leaving group
_______________
71There is a slight difference between a radical being a Nucleophile or being a Base.
Base:
In general those radical groups, which are smaller in size i.e., have a high concentration of charge on the most electronegative atom, tends to be a stronger atom. Or in other words you can say that those groups are stronger base, which have a weaker conjugate acid and vice versa.
Nucleophile: The role of a nucleophile also depends on the nature of the solvent and size of the atom bearing the lone pairs or the negative charge.
As for example, SH- is a stronger nucleophile compared to OH- but a weaker base.
Note: I have written my explanation is very short. It might sound confusing.
1Nucleophile strength increases down a group of the periodic table..... but due to bulkiness of the substrate it decreases.
If the nucleophile atoms are from the same period,then nucleophilicity runs parallel with basicity!
