JAMB - Chemistry (1978 - No. 13)
When each of the nitrates of Potassium, Magnesium and iron is heated,
all the nitrates decompose to their oxides
the nitrate of magnesium gives the nitrite and oxygen
the nitrates of magnesium and iron give the oxides
the nitrate of iron gives the nitrite and oxygen
the nitrate of the magnesium is not decomposed
Giải thích
When heated, the nitrates of potassium, magnesium, and iron decompose as follows:
- Potassium nitrate (KNO₃) decomposes to potassium nitrite (KNO₂) and oxygen (O₂).
- Magnesium nitrate (Mg(NO₃)₂) decomposes to magnesium oxide (MgO) and nitrogen dioxide (NO₂) and oxygen (O₂).
- Iron(III) nitrate (Fe(NO₃)₃) decomposes to iron(III) oxide (Fe₂O₃) and nitrogen dioxide (NO₂) and oxygen (O₂).
So, all three nitrates would not decompose to their respective oxides except Nitrates of Magnesium and Iron.
The correct answer is C.