What is the number of moles of $sp^2$ hybrid carbon atoms in one mole of $hexa-1,4-diyne$?

Match the four starting materials $(P, Q, R, S)$ given in List-$I$ with the corresponding reaction schemes $(I, II, III, IV)$ provided in List-$II$ and select the correct answer using the code given below the lists. Codes: $P \quad Q \quad R \quad S$

Which of the following is an incorrect statement about the heats of combustion?

What are $X$ and $Y$ respectively in the following sets of reactions?
$I. \ CH_3CH_2CH_2OH \xrightarrow{PBr_3} X$
$II. \ CH_3CH=CH_2 \xrightarrow{HBr, (C_6H_5COO)_2} Y \text{ (major)}$

Which of the following reactions do not represent the major product of given Birch reductions?

The major product of the reaction is: