Enumerate different methods to prepare aldehyde compounds.

(N/A) Aldehyde compounds can be prepared by the following methods:
$i$. Oxidation of primary alcohols using $PCC$ or $CrO_3$.
$ii$. Dehydrogenation of primary alcohols over $Cu$ catalyst at $573 \ K$.
$iii$. Ozonolysis of alkenes followed by reduction with $Zn/H_2O$.
$iv$. Rosenmund reduction: Hydrogenation of acyl chlorides using $Pd/BaSO_4$.
$v$. Stephen reaction: Reduction of nitriles with $SnCl_2/HCl$ followed by hydrolysis.
$vi$. Reduction of nitriles and esters using $DIBAL-H$ followed by hydrolysis.
$vii$. Etard reaction: Oxidation of toluene using $CrO_2Cl_2$ followed by hydrolysis.
$viii$. Oxidation of toluene with $CrO_3$ in acetic anhydride.
$ix$. Side chain chlorination of toluene followed by hydrolysis.
$x$. Gatterman-Koch reaction: Formylation of benzene using $CO$ and $HCl$ in the presence of anhydrous $AlCl_3$ or $CuCl$.