" (2) Acetylene to acetaldehyde."

How will you convert: (a) acetylene to acetaldehyde (b) ethylene to acetylene (c) isopropylbromide to n-propylbromide (d) acetic acid to methane ?

Conversion of Acetylene into acetaldehyde

How can the following conversions be brought about : Acetaldehyde to acetaldehyde phenyl hydrazone.