In the following reaction sequence, X and Z, respectively are:

$\displaystyle \mathrm{X}=\mathrm{POCl}_3 ; \mathrm{Z}=$

$\displaystyle \mathrm{X}=\mathrm{POCl}_3 ; \mathrm{Z}=\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{CH}_2-\mathrm{Br}$

$\displaystyle \mathrm{X}=\mathrm{H}_3 \mathrm{PO}_3 ; \mathrm{Z}=$

$\displaystyle \mathrm{X}=\mathrm{H}_3 \mathrm{PO}_3 ; \mathrm{Z}=\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{CH}_2-\mathrm{Br}$