The choice of method for extracting a metal from its ores depends on the

Analysis

The question asks for the primary factor that determines how a metal is extracted from its ore. In metallurgy, different metals have different affinities for oxygen and other non-metals, which dictates the energy required to isolate them.

Concept Explanation

The extraction of metals is based on their reactivity. The more reactive a metal is, the more strongly it holds onto its ore (usually oxides, sulfides, or carbonates), and the more energy is required to reduce it to its metallic state.

The Electrochemical Series (or Reactivity Series) ranks metals based on their tendency to lose electrons (oxidation).

• Highly reactive metals (e.g., Potassium, Sodium, Calcium): These are at the top of the series. They hold onto their ores so strongly that they cannot be reduced by carbon or hydrogen. They must be extracted via electrolysis of their molten salts.
• Moderately reactive metals (e.g., Zinc, Iron, Lead): These are in the middle of the series. They can be extracted by reduction with carbon or carbon monoxide in a blast furnace.
• Less reactive metals (e.g., Copper, Silver, Gold): These are at the bottom of the series. They are often found in their native state or can be extracted by simple thermal decomposition or roasting.

Step-by-Step Solution

1. Evaluate the options: • A (Strength of the core): "Core" is not a standard metallurgical term for ore properties; this is irrelevant. • B (Position of the metal in the electrochemical series): This determines the metal's reactivity, which directly dictates whether electrolysis, chemical reduction, or thermal decomposition is needed. • C (Source of the core): While the location of the ore matters for mining, it does not dictate the chemical method of extraction. • D (Position of the metal in the periodic table): While reactivity trends exist in the periodic table, the electrochemical series is the specific tool used to predict the ease of reduction and the required extraction method.

2. Conclusion: The position of a metal in the electrochemical series provides the most accurate guide to its reactivity, which is the deciding factor for the extraction method.

Exam Tip

Remember the "Reactivity Ladder":

• Top (High reactivity): Electrolysis (needs lots of electricity).
• Middle (Moderate reactivity): Reduction with Carbon (needs heat).
• Bottom (Low reactivity): Heat alone or naturally occurring (needs little to no effort).