Reagents used Etard reaction (I) and Stephen reaction (II) are :

Explanation

The reagents used in Etard reaction (I) is `CrO_(2)` and Stephen reaction (II) is `SnCI_(2)` /HCI. In Etard reaction toluene in presence of chromyl chloride gives a brown complex which gives benzaldehyde

In Stephen .s reaction nitriles underges reduction followed by hydrolysis to give aldehyde.
`CH_(3)-C equiv N+2[H] underset("Ether")overset(SnCI_(2)//HCI)rarr`
`CH_(3)-CH=NH.HCIoverset(H_(2)"O"//H^(+))rarr CH_(3)CHO+NH_(4)CI`