Indicate which of the metallation reactions given below would be thermodynamically favourable on the basis of the pKa data in non-aqueous media provided.

What is the underlying principle that determines whether the reaction occurs?
(a) C6H5Li + C6H5CH3 → C6H5CH2Li + C6H6
(b) LiCH2CH=CH2 + C6H5CH3 → C6H5CH2Li + CH3CH=CH2
(c) CH3Li + HC≡CH → HC≡CLi + CH4
(d) LiH + CH3CH=CH2 → LiCH2CH=CH2 + H2
(e) LiCH3 + CH3CH=CH2 → LiCH2CH=CH2 + CH4

Table pka values
HC≡CH 24
C6H6 37
CH4 48
C6H5CH3 35
H2 35
CH3CH=CH2 43

I don't understand anything in this question.. Can someone please give me a little help?

1 answer

Here is a site you can read. It may not be the BEST but if you follow it carefully you will see how it's done.
http://www.masterorganicchemistry.com/2010/09/29/how-to-use-a-pka-table/
Basically, if the acid produces a WEAKER acid the reaction will proceed. If not, the reaction will not proceed. Here is the first one.
pKa = 37 for C6H6 (the acid product)
pka = 35 for C6H5CH3 (the acid reactant)
Since 35 is a stronger acid than 37 the reaction will proceed.
I'm assuming you know how to determine which is the acid and which is the base.