a) nMgO=10/40=0,25(mol)
PTHH: MgO + 2 HCl -> MgCl2 + H2O
0,25_________0,5_________0,25(mol)
b)mHCl=0,5.36,5=18,25(g)
=> mddHCl=18,25/20%= 91,25(g)
c)PTHH: 2 HCl + Ba(OH)2 -> BaCl2 + 2 H2O
0,5____________0,25(mol)
=>VddBa(OH)2= 0,25/2=0,125(l)=125(ml)