Complete the following equations:
i) `2HCHO+" conc. KOH"rarr`
ii) `CH_(3)CHO+NH_(2)OHrarr`
iii) `CH_(3)COOH+PCl_(5)rarr` 

Explanation

i) Two molecules of aldehydes which do not contain `alpha -` hydrogen atom react with strong alkali and undergo redox reaction with strong alkali and undergo redox reaction to produce a primary alcohol and a salt of carboxylic acid. This rection is called as cannizaro.s reaction.

ii) Acetaldehyde reacts with hydroxylamine to gice acetaldoxime

iii) Carboxylic acids reacts with phosphorus pentachloride to form corresponding acid chlorides
`underset("(acetic acid)")(CH_(3)-COOH+PCl_(5))rarr underset("(acetyl chloride)")(CH_(3)-COCl+POCl_(3)+HCl)`