Acetaldehyde reacts with $Cl_2$ (in excess) to give

Which among the following has the highest boiling point?

What is formed when benzaldehyde reacts with chlorine in the absence of a catalyst?

In the presence of peroxide,styrene reacts with $HBr$ to give $X$. When $X$ is reacted with magnesium in dry ether followed by $CO_2$ and hydrolysis,it gives $Y$. Treatment of $Y$ with $PCl_5$ and then with $H_2, Pd-BaSO_4$ gives $Z$. What is $Z$?

What will be the product obtained when formaldehyde is treated with conc. $NaOD$ followed by treatment with conc. $H_2SO_4$?

What is the major product formed when salicylaldehyde is reacted with $2$ equivalents of bromine in glacial acetic acid at $0^{\circ} C$?