org chem

3. SO2Cl2 for chlorination by substitution. Works in the same way as SOCl2 works but yields less than it and have few complications.
Ag2O is used as oxidizing agent isn't it? Perform differently in dry and wet medium

Q1 is simple enough.. This is the reaction which shows the dimerisation of alkenes. After action of H+ (from H2SO4), it yields a carbocation which reacts on another molecule of alkene(here isobutene) as per markownikoff principle and yields major product. Similarly a minor product.

Ag₂O is the principal reagent in BORODIENE HUNSDIECKER REACTION !

SO₂Cl₂ gives Allylic Substitution.

n Ag₂O i) R-X + dry(Ag₂O) -----> R-O-R (Ether)
ii) As Debo mentioned, used in the 1st step of Hunsdeicker.
iii) Smtimes written in place of Tollen's reag.

(Aur kuch use yaad nahi aa raha..)

@ debotosh can you please indicate the stereochemistry fo rhte answer you've given for the third one ?? that'll make the question a bit more interesting :)