Which would be the stronger nucleophile in a polar aprotic solvent?

[lha08]

Homework Statement

Which would be the stronger nucleophile in a polar aprotic solvent?
a) H2O or H2S
b) (CH3)3P or (CH3)3N

Homework Equations

The Attempt at a Solution

I'm really confused because in my book, it says that in protic solvents, the larger atoms (I-) are stronger nucleophiles than smaller ones (F-). Then it says that it is opposite for when it is an aprotic solvent (e.g. F- is more nucleophilic than I-)
In this case, the answer to b) is H2S and c) is (CH3)3P, but shouldn't it be the opposite??

 

[omkar13]

The answers given for the question is correct and the concept given is wrong.consider protic solvent it consists of H+ ions since bonds between similar sized atoms is strong,the bond between smaller atoms will be stronger if F- is in polar protic solvent,it forms HF molecule which will be more stable than other halogen hydrides