$CH_3-CH(OH)-CN$ is

What is $Z$ in the following reaction sequence?
$C_6H_5NH_2$ $\xrightarrow[(i) NaNO_2 + HCl / 273 \ K]{(ii) H_3PO_2 + H_2O}$ $\xrightarrow[(iii) CO, HCl, \text{anhydrous } AlCl_3/CuCl]{} Z$

The reagent used in Gatterman-Koch aldehyde synthesis is

What is the name of the given reaction?

Which of the following reactions uses $SnCl_2/HCl$ as a catalyst?

Which sequence represents the best synthesis of hexanal?
$CH_3CH_2CH_2CH_2CH_2CH=O$ (Hexanal)