Answer
See the answer below.
Work Step by Step
a) From Dalton's law and the stoichiometry:
$P_{N_2}=6/(6+1+12+10)×4.2\ atm=0.87\ atm$
b) From ideal gas law:
$PV=nRT$
$n=4.2\ atm×1.5\ L/0.082057\ atm.L/mol.K\div (450+273)\ K$
$n=0.106\ mol$
From stoichiometry:
$0.106\ mol×4/(6+1+12+10)=$
$0.0146\ mol$ of nitroglycerin
$0.0146\ mol×227.09\ g/mol=3.31\ g$
