Questions and Answers
Which method is primarily used to extract highly reactive metals from their ores?
What term describes the undesirable impurities found in ore?
Which metals are typically extracted through the self-reduction method?
What is the primary reason why extracting highly reactive metals cannot be achieved through heating with carbon?
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What does metallurgy refer to in the context of metal extraction?
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Which of the following is not a method used for metal extraction based on reactivity?
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Which of the following elements is considered very less reactive and found in a metallic state in nature?
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What is the process called when gangue is removed from ore?
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Which method involves igniting a mixture to obtain pure metals?
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What type of metals are typically reduced using electrolytic methods?
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During the electrolytic refining process, the impure metal serves as the _____?
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What is the product formed at the cathode during the electrolysis of sodium chloride?
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Which of the following is NOT a common impurity typically removed in the refining of metals?
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What is the role of the ignition mixture in the thermite reaction?
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What by-product is typically formed from the reaction of iron(III) oxide and aluminum?
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What type of oxide is formed when non-metals react with oxygen?
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What occurs to impurities during the electrolytic reduction process?
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What phenomenon explains why calcium floats when formed in the presence of water?
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Which of the following is a non-lustrous metal?
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Which of the following metals will not displace copper from a solution of its salts?
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What is the green substance formed on a copper plate exposed to air for a week?
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What is the primary reason sodium chloride conducts electricity only in molten or aqueous states?
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Which process involves depositing metal onto a surface using electric current?
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What compound is formed by the reaction of iron with steam over prolonged exposure?
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Which element reacts with oxygen to form a compound that has a high melting point and is soluble in water?
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What is a common example of an alloy that consists of copper and zinc?
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What happens to metal ions at the cathode during electrolysis?
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Which method prevents corrosion by forming a protective layer of zinc?
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Why do alloys generally exhibit increased resistance to corrosion?
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What is the primary function of sacrificial protection in preventing corrosion?
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What is the outcome when calcium is added to water?
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What is the result of oxidation at the anode during electrolysis?
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Which property is NOT true for sulphur as a non-metal?
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What explains the acidic nature of magnesium oxide?
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What characteristic of ionic compounds is highlighted by their ability to conduct electricity?
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Why are sodium and potassium metals stored under kerosene?
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Which statement correctly describes aluminium oxide?
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What happens to a blue copper sulphate solution when an iron strip is introduced?
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What indicates that magnesium is a metal based on its properties?
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Which of the following accurately reflects the behavior of compounds formed by metals and non-metals?
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Study Notes
Occurrence of Metals
- Earth's crust is the primary source of metals; seawater contains soluble salts.
- Minerals are naturally occurring elements or compounds, while ores are minerals from which metals can be profitably extracted.
Extraction of Metals from Ores
- Metallurgy refers to the extraction and refinement of metals from ores.
- Extraction techniques depend on metals' reactivity:
- Highly Reactive Metals: Extracted via electrolysis due to strong bonds with ore components (e.g., Potassium, Sodium, Calcium, Magnesium).
- Moderately Reactive Metals: Extracted using the reduction process with agents like coke (e.g., Zinc, Iron, Lead).
- Less Reactive Metals: Extracted through self-reduction by heating (e.g., Copper, Mercury).
- Very Less Reactive Metals: Found in free metallic state (e.g., Silver, Gold, Platinum).
Concentration of Ores
- Gangue (undesirable impurities) must be removed to enrich ores.
- Low reactivity metals undergo self-reduction with heat, allowing the conversion of sulfide ores to oxides.
Methods of Metal Extraction
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Thermite Reaction: A mix of concentrated oxide ore and aluminum reduces metal oxide to metal (e.g., Chromium and Iron).
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Electrolytic Reduction: Reactive metals (e.g., Na, K, Mg) are reduced from molten oxides or hydroxides using electric current.
Refining/Purification of Metal
- Impurities removed during refining include unreacted ore, byproducts, and non-metals.
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Electrolytic Refining of Copper:
- Uses impure copper as anode and pure copper as cathode; metal ions reduce on cathode.
Corrosion
- Gradual deterioration of metals due to moisture, air, or chemicals (e.g., rusting of iron).
Prevention of Corrosion
- Coating: Paint, oil, or grease prevents moisture and air contact.
- Alloying: Alloys exhibit enhanced resistance; e.g., stainless steel.
- Galvanization: Coating iron with zinc for protection from corrosion.
- Electroplating: Coating one metal with another using electric current.
- Sacrificial Protection: Mg prevents iron corrosion by undergoing oxidation instead.
Alloys
- Homogeneous mixtures of metals or non-metals enhance properties like hardness and strength (e.g., Brass = Copper + Zinc, Bronze = Copper + Tin).
Previous Year Questions
- Questions include arrangements of metals by reactivity, valency details, reactions with water, and features of ionic compounds.
- Responses involve reasoning about properties of metals vs. non-metals, stimulus for alloy formation, and behaviors within chemical reactions.
Key Points on Ionic Compounds
- Formed by the transfer of electrons from metals to non-metals.
- General properties include high melting points, solubility in water, and conductivity in molten and aqueous forms.
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Description
Test your knowledge on the occurrence of metals in Earth's crust and the extraction processes involved in metallurgy. This quiz covers essential concepts such as minerals, ores, and refining techniques used to obtain pure metals. Perfect for students studying materials science or geology.