The reaction Fe₂O₃ + 2Al → Al₂O₃ + 2Fe is an example of:
A. Combination
B. Decomposition
C. Double displacement
D. Displacement
Answer: Option D
Solution (By JKExamLibrary)
Aluminium displaces iron from iron(III) oxide because Al is more reactive. This is a single displacement (or thermite) reaction. Also redox: Al oxidized, Fe reduced. Combination: one product; decomposition: one reactant.
Explanation:
Refining is the final step in metallurgy to obtain pure metal. Poling is used for copper to remove oxide impurities. Liquation separates low-melting metals (like tin) from high-melting impurities. Zone refining is used for producing ultra-pure semiconductors (like Si, Ge) based on the principle that impurities are more soluble in the molten state.
Explanation:
LPG (propane/butane) is odorless. A small amount of strong-smelling mercaptan (ethanethiol) is added to help detect gas leaks, preventing accidents. Natural gas also has odorant. Mercaptans contain sulfur, and their smell is detectable at very low concentrations. Calorific value, temperature, performance are unaffected. Safety is primary.
Explanation:
Two reactants combine to form a single product, so combination (also called synthesis). No oxidation state change, so not redox. Decomposition is opposite.
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