How would you do the following conversions in not more than two steps?
(i) Propanone to Propene
(ii) Propanal to Butaonone
(iii) Ethanol to 3-Hydroxybutanol
(iv) Benzaldehyde to Benzophenone
(v) Benzaldehyde to `alpha`-Hydroxyphenylacetic acid
(vi) Benzaldehyde to 3-Phenylpropan -1-ol

Explanation

(a) `CH_(3)COCH_(3)overset(LiAlH_(4))toCH_(3)overset(OH)overset(|)CH-CH_(3)overset(H^(+),453K)toCH_(3)CH=CH_(2)`
(b) `CH_(3)CH_(2)CHOoverset(CH_(3)MgBr)underset(H_(3)O^(+))toCH_(3)-CH_(2)-overset(OH)overset(|)CH-CH_(3)overset(K_(2)Cr_(2)O_(7)//H^(+))toCH_(3)CH_(2)overset(O)overset(||)C-CH_(3)`
( c) `CH_(3)CH_(2)OHoverset([O])tounderset("2 moles")(CH_(3)CHO)overset(OH^(-))underset("Aldol condensation")toCH_(3)-overset(OH)overset(|)CH-CH_(2)CHO`