Question

I think the Nucleophilicity of the leaving material on polar protic solvents that

It is the opposite with the basicity (because nucleophilicity increase down a column)

Is it true that Basicity opposites the nucleophility in polar protic solvents?

I think that when comparing the nucleophilicity of CH3COO- CH3CH2O-

The CH3CH2O- is bulky compared to CH3COO- so I think the CH3CH2O- would be less nucleophilic

but the answer says the CH3COO- is less nucleophilic because it is less basic.

I wonder what's wrong with my idea (linking bulkiness and nucleophility)

Is there any point idea that Basicity opposites the nucleophility in polar protic solvents?

Answer 1

Hello student.

In a period or row basicity and nucleophilicity runs parallel i. e. Stronger base will be stronger nucleophile and weaker base will weaker nucleophile.

In a column or group basicity and nucleophilicity runs in opposite direction i. e. Weaker base will be stronger nucleophile and stronger base will be weaker nucleophile.

CH3COO-  and CH3CH2O- have same donor atom so basicity and nucleophilicity runs parallel. Weaker base will be weaker nucleophile and stronger base will be stronger nucleophile. So

CH3COO- is a weaker base so it is weaker nucleophile.

I have mentioned basic important information.

Nucleophile :- Nucleophile are those particle which can donate electoon paio to generate sigma bond with carbon Nuiº tųC-C1 - HC-Nu + c Nudeophile Base :- Base are abstract a those proton particle which can in the solution. Biº Base + HCl + B-H + cie Nucleophilicity → tendency to Bond with bom Grbon Basicity → tendency to abstract it factors affecting strength of Nucleophile O charge Nucleophile is stoonger compared to Neutral. C conjugate Base > Neutral) 8H >tho sů > Hes @ Nucleophilicity & Size of donor atom Mon cuisine roccio a Broc I Hoo (sh On moving top to botton down the group from Nucleophilicity increases. 3 Nucleophilicity a Electronegativity of donor atom N o f Electronegativity ises s a Electronegativity ases - Nucleophilicity Ises SH / ci Nth > On >fo ☺ other factors If donor atom is same then nucleophile in which delocalization of election is less nucleophilic Hz C- CH2 - 0 sno delocalization - od election delocalization of election due to resonance = less nucleophilic → More nucleophilic Donor atom → Oxygen Delocalization of election. ܨ ܝ fleܟ

Hopefully your doubt will be cleared.

Thanks