How will you convert acetaldehyde into the following compounds ?
But-2-enal

Explanation

`2CH_(3)CHOoverset(dil.NaOH)toCH_(3)-underset(OH)underset(|)(CH)-CH_(2)CHOunderset(Delta,-H_(2)O)overset(H^(+))tounderset("But-2-enal")(CH_(3)-underset(H)underset(|)Cequivunderset(H)underset(|)C.CHO)underset("Tollens. reagent")overset([Ag(NH_(3))_(2)]^(+)OH^(-))tounderset("But-2-enoic acid")(CH_(3)CH=CHCOOH)underset(Ni.H_(2))overset("reduction")tounderset("Butan-1-ol")(CH_(3)CH_(2)CH_(2)CH_(2OH)underset("Oxidation")overset(KMnO_(4)//H^(+))tounderset(CH_(3)CH_(2)CH_(2)COOH)`