Explanation

(a)
2-hydroxypropane or secondary alcohol is oxidised into propanone (corresponding carbonyl compound because in 2-hydroxypropane, secondary alcoholic group is present and it is oxidised into ketone).
$CH_{3} - CH - CH\overset{\ \ \ \ \lbrack O\rbrack\ \ \ \ \ \ }{\rightarrow}CH_{3} - C - CH_{3}$
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$OH$ $\ \ O$
2-hydroxyprone propanone
(s-alcohol) (ketone)