The salt which in solution gives a pale green precipitate with sodium hydroxide solution and a white precipitate with barium chloride solution is :

1. Iron (III) sulphate
2. Iron (II) sulphate
3. Iron (II) chloride
4. Iron (III) chloride

Iron (II) sulphate

Reason

1. Pale green precipitate with sodium hydroxide (NaOH):
   • Iron (II) salts (like Iron (II) sulphate) give a pale green precipitate of iron (II) hydroxide, Fe(OH)₂:
     FeSO₄ + 2NaOH ⟶ Fe(OH)₂↓ (pale green) + Na₂SO₄
   • Iron (III) salts would give a reddish-brown precipitate instead (Fe(OH)₃)
2. White precipitate with barium chloride (BaCl₂):
   • The sulphate ion (SO₄^2-) reacts with barium chloride to form barium sulphate (BaSO₄), a white precipitate:
     FeSO₄ + BaCl₂ ⟶ BaSO₄↓ (white) + FeCl₂
   • This confirms the presence of a sulphate ion in the salt.

So, the salt must be an iron (II) salt (due to the pale green ppt) containing sulphate (due to white ppt with BaCl₂), i.e., Iron (II) sulphate.