Identify the substrate ' X ' in the following reaction.

$$ \mathrm{X}+\underset{\text { (air) }}{\mathrm{O}_2} \xrightarrow[\text { ii) dil HCl } \Delta]{\text { i) Co-naphenate } 423 \mathrm{~K}} \text { Phenol }+ \text { Acetone } $$

Identify the product ' $Z$ ' in the following series of reactions.

$$ \text { Ethanol } \xrightarrow[\Delta]{\mathrm{SOCl}_2} \mathrm{X} \xrightarrow[\text { Dry ether }]{\mathrm{Mg}} \mathrm{Y} \xrightarrow{\mathrm{NH}_3} \mathrm{Z} $$

Identify the structural formula of phloroglucinol.

Which among the following compounds has lowest boiling point?