$n_{Al}=5,4/27=0,2mol$
$4Al+3O_2\overset{t^o}\to 2Al_2O_3$
$a/$
Theo pt :
$n_{O_2}=3/4.n_{Al}=3/4.0,2=0,15mol$
$⇒V_{O_2}=0,15.22,4=3,36l$
$b/$
Theo pt :
$n_{Al_2O_3}=1/2.n_{Al}=1/2.0,2=0,1mol$
$⇒m_{Al_2O_3}=0,1.102=10,2g$
$c/$
$2KMnO_4\overset{t^o}\to K_2MnO-4+MnO_2+O_2$
Theo pt :
$n_{KMnO_4}=2.n_{O_2}=2.0,15=0,3mol$
$⇒m_{KMnO_4}=0,3.158=47,4g$