Benzene reacts with concentrated sulphuric acid (slowly) or fuming sulphuric acid (more quickly) to form benzene sulphonic acid. The electrophile is sulphur trioxide.
a) Explain the source of the sulphur trioxide if you are using
(i) concentrated sulphuric acid
(ii) fuming sulphuric acid.
b) Explain why sulphur trioxide is an electrophile.
c) Give the full mechanism for the reaction