Mark the correct increasing order of reactivity of the following compounds with HBr / HCl.
  

1.  I < II < III 

2.  II <I < III

3.  II < III < I 

4.  III < II < I 

Which of the following reagents can be used to oxidize primary alcohols to aldehydes?

I.  ${\mathrm{CrO}}_3$ in anhydrous medium

II.  ${\mathrm{KMnO}}_4$ in acidic medium

III.  Pyridinium chlorochromate

IV.  Heat in the presence of Cu at 573K

Choose the correct option
1. (I, II, III)
2. (II, III, IV)
3. (I, III, IV)
4. (I, II, IV)