IIT JEE , AIEEE Forum - Chemistry , Organic Chemistry

neeleshv

IN

R-CO-X + Nu^-

R-CO-Nu

What is the order of nucleophilicity for

NH2^-, CH₃O^-, ^-OCOCH₃, OH^-

ambuj123

Seee the weaker the base the better is it's leaving ability

Now here acidity order os

CH3COOH>H2O>CH3OH>NH3

this is acidity order so basic ability ould be reverse

So weakest base is CH3COO-

so it should be the best leaving group

neeleshv

Basicity and nucleophilicity do not necessaliry have the same order

nik_d_1

NH₂^->OH^->CH₃O^->^-OCOCH₃

beck2ham

well, ur question has to be tackled in a different manner.

In case of CH₃O^-, ^-OCOCH₃, OH^-, since the nuecleophilic and the basic sites are same, nucleophilicity will parallel basicity.

Thus for the above mentioned, the correct order would be, as follows.

CH₃O^-> OH^-> ^-OCOCH₃

And now, we only need to decide the place for NH2^{- .}

Since, the medium will be highly polar, NH2^-we will be less attracted towards medium molecules in comparison to OH^-. Thus, NH2^-> OH^-.

But , in case of CH₃O- , attraction will be even less than NH2^- .

Thus the correct order would be as follows:

CH₃O^-> NH2^- > OH^- > ^-OCOCH₃

Please rate the answer if u find it beneficial.

neeleshv

experts please answer fast

madhusudan.chavan

10308

Nucleophilicity is the ability of a reagent to donate a pair of electrons to the carbon atom. The greater the nucleophilicity, the more rapid should be its S_N² reaction.

1.Nucleophilicity increases with increasing negative charge on the atom e.g., OH^-> H₂O

2.It increases with increasing atomic number down a group in the periodic table, thus

I^- > Br ^- >Cl ^- > F^-in a protic polar solvent.

3.It decreases with increasing atomic number along a period in the periodic table

C^- > N ^-> O ^- > F ^?

4.Conjugate base of a weaker acid is a stronger base.

Order of acidity is NH₃ < H₂O <CH₃OH < CH₃COOH

Order of basicity is NH₂^- > OH ^- > CH₃O ^- > CH₃COO ^?

beck2ham

Well................is acetic acid a weaker acid than water???

magiclko

no doubt acetic acid, water is said to be neutral, acetic acid is weak acid, but still its an acid...

moreover, on loosing H, acetic acid's -ve charge gets resonance stabilised...

so its better acid

Ask & Discuss Questions with Community & Experts