Do you think Q2 (assuming it is R-S-S-R) should be oxidation since it lost H's?
I would say so, yes.
Also, So according the Wikipedia page... so does that mean LiAlH4 only reduces esters and carboxylic acids? Not anything like carboxylate?
Two things, first off - the article I linked to gives the reactions of LiAlH4
with aldehydes, ketones, esters, azides, carboxylic acids, nitriles, amides and epoxides. It is not limited to carboxylic acids and esters.
Secondly, the first reaction that happens when a carboxylic acid comes into contact with LiAlH4
is an acid-base reaction that produces the corresponding lithium carboxylate, which is then reduced - so carboxylates will be reduced by LiAlH4
. This reagent will reduce pretty much anything, it is extremely powerful - try to identify the product you would get in each case for Q3.