doubts4

ankit

for i) can't it be Cu and CrO₃ as well

2) use any oxididsing agent...
acidic soln of chromate or dichromate
OR Cu/heat

etc.....

i think CrO3 is used mostly for 2° alcohol .
PCC is used for primary alcohol.

Please correct if wrong.

CrO3 is a strong oxidising agent so some part of it may converted to acid ...
in case of Cu u have to specify particular temp... like 300deg.C so it is preferred that u use PCC as ur oxidising agent...

in the 2nd case u may use any oxidising agent....