Ozonolysis of which compound gives $OHC-CH_2-CH(CH_3)-CH_2-CHO$?

In the following reaction,$P$ gives two products $Q$ and $R$ each in $40 \,\%$ yield. If the reaction is carried out with $420 \,mg$ of $P$,the reaction yields $108.8 \,mg$ of $Q$. The amount of $R$ produced in the reaction is closest to $....\, mg$.

The products $Q$ and $R$ in the following reactions respectively are:
$H_2 + CH_3-C \equiv CH$ $\xrightarrow{\text{Lindlar's catalyst}} P$ $\xrightarrow[Zn + H_2O]{O_3} Q + R$

The alkene which on ozonolysis yields acetone is

During the debromination of $meso-2,3-dibromobutane$,the major compound formed is:

In the reaction sequence:
$Cyclohexane$ $\xrightarrow{hv/Cl_2} (X)$ $\xrightarrow{alc. KOH/\Delta} (Y)$ $\xrightarrow[(ii) H_2O/Zn]{(i) O_3} (Z)$
$(Z)$ will be :