Glycerol has strong intermolecular hydrogen bonding; therefore,it is:

Which sequence of steps describes the best synthesis of $2-$phenylpropene?

Identify the product $B$ in the following series of reactions.
$CH_3-CH_2-CH_2-OH$ $\xrightarrow{Al_2 O_3, 623 \ K} A$ $\xrightarrow[(ii) H_2 O]{(i) \text{conc. } H_2 SO_4} B$

Which Grignard reagent gives $2-$methylpropan$-1-$ol upon reaction with methanal followed by hydrolysis?

Identify the product formed when $(R)-2-$butanol and $(S)-2-$butanol react with $(R,R)-$tartaric acid in an acidic medium.

$CH_3 CH_2 OH \underset{\text{step-}1}{\stackrel{Cl_2}{\longrightarrow}} CH_3 CHO$ $\underset{\text{step-}2}{\stackrel{3 Cl_2}{\longrightarrow}} Cl_3 CCHO$
In the above reactions,the role of $Cl_2$ in step-$1$ and step-$2$ respectively is: