Which of the following is a chemical property of matter?
A. Flammability
B. Melting point
C. Density
D. Boiling point
Answer: Option A
Solution (By JKSSB Mock Tests)
Flammability describes how a substance reacts with oxygen to burn, which is a chemical change. Boiling point, density, and melting point are physical properties because they can be observed without changing the chemical identity of the substance. Chemical properties are only observed during a chemical reaction.
Explanation:
Thermite process uses a mixture of aluminium powder and iron(III) oxide: Fe₂O₃ + 2Al → 2Fe + Al₂O₃ + heat. The reaction is highly exothermic, producing molten iron that is used to join railway tracks. Aluminium acts as a reducing agent. Copper, zinc, iron are not used as the reducing agent in this process.
Explanation:
DAP (diammonium phosphate) contains N (18%) and P₂O₅ (46%). Urea only N; MOP (muriate of potash) only K; SSP only P. NPK mixtures provide all three.
Explanation:
The salt bridge (often KCl-agar) allows ion migration to maintain electrical neutrality in half-cells, completing the circuit. It prevents direct mixing of electrolytes.
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