The process of roasting is used for: MCQ with Answer and Explanation

The process of roasting is used for:
A. Carbonate ores
B. Native metals
C. Sulfide ores
D. Oxide ores
Answer: Option C
Solution (By JKExamLibrary)
Roasting converts sulfide ores to oxides by heating in excess air: 2ZnS + 3O₂ → 2ZnO + 2SO₂. Calcination is for carbonates; leaching for others.

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Practice More chemistry Questions

Question #1
In the Haber process for the manufacture of ammonia, the catalyst used is:
A. Finely divided Iron (Fe)
B. Vanadium pentoxide (V₂O₅)
C. Nickel (Ni)
D. Platinum (Pt)

Correct Answer: Option A


Explanation:
The Haber process synthesizes ammonia from nitrogen and hydrogen (N₂ + 3H₂ ⇌ 2NH₃). Finely divided iron acts as the catalyst, often with molybdenum as a promoter, to increase the rate of reaction at high pressure and moderate temperature. V₂O₅ is used in the Contact process.

This question belongs to: Science chemistry
Question #2
The main ore of copper is:
A. Cinnabar
B. Copper pyrites
C. Haematite
D. Bauxite

Correct Answer: Option B


Explanation:
Copper pyrites, also known as chalcopyrite, is the most important and abundant ore of copper. Its chemical formula is CuFeS2. Bauxite is the ore of aluminum, cinnabar is the ore of mercury, and haematite is the primary ore of iron.

This question belongs to: Science chemistry
Question #3
Soap works by forming structures called micelles. The hydrophobic tails dissolve in:
A. The oily dirt
B. Water
C. Air
D. The soap dish

Correct Answer: Option A


Explanation:
The long hydrocarbon chain (tail) of soap is non-polar and hydrophobic, so it dissolves into the oily/greasy dirt particle. The ionic head (hydrophilic) remains in the water. This forms a micelle around the dirt, emulsifying it and allowing it to be washed away. The tail-dirt interaction is via van der Waals forces.

This question belongs to: Science chemistry