Answer
a) Sodium Carbonate
b) Ammonium Sulfide
c) Barium Phosphate
d) Tin (II) Nitrite
Work Step by Step
$a) Na_{2}CO_{3}$= Sodium Carbonate
$b) (NH_{4})_{2}S$ = Ammonium Sulfide
$c) Ba_{3}(PO_{4})_{2}$= Barium Phosphate
$d) Sn(NO_{2})_{2}$= Tin (II) Nitrite