Metal MCQ Quiz - Objective Question with Answer for Metal - Download Free PDF

The correct answer is 1 and 3 only.

Key Points

• Statement 1 is correct: Metals of medium reactivity are commonly extracted from sulphide ores through roasting to convert them into oxides, followed by reduction to extract the metal.
• Statement 3 is correct: Metals of medium reactivity can also be extracted from carbonate ores by calcination, which decomposes the carbonates into oxides, followed by reduction to extract the metal.
• Statement 2 is incorrect: Metals of high reactivity are not directly extracted from sulphide ores by roasting; they are generally extracted through electrolysis of molten compounds.
• Statement 4 is incorrect: Metals of low reactivity are extracted directly from their ores by roasting, not electrolysis, as they do not form compounds requiring electrolysis.
• Hence, only statements 1 and 3 are correct, as they align with the established processes for metal extraction based on reactivity.

Additional Information

• Roasting: A process in which sulphide ores are heated in the presence of oxygen, converting them into oxides. For example, ZnS (zinc sulphide) is roasted to form ZnO (zinc oxide).
• Calcination: A thermal decomposition process where carbonate ores are heated in the absence of air to produce oxides. For example, CaCO₃ (calcium carbonate) is calcined to form CaO (calcium oxide).
• Reduction: The process of extracting metals from their oxides by heating with a reducing agent, such as carbon, or by electrolysis for highly reactive metals.
• Electrolysis: A method used for extracting highly reactive metals like sodium, potassium, and aluminium by passing an electric current through their molten compounds.
• Reactivity Series: A series that ranks metals based on their reactivity. Metals at the top (e.g., potassium, sodium) are highly reactive, while those at the bottom (e.g., gold, platinum) are least reactive.

Answer: Cu, Ag, Au.​Key Points

• Reactivity Series and Metal Extraction:

  • Metals at the bottom of the activity series are the least reactive.

  • These metals are often found in the free state, such as gold, silver, platinum, and copper.

  • Copper and silver are also found in combined states as their sulphide or oxide ores.

• Highly Reactive Metals:

  • Metals at the top of the activity series (K, Na, Ca, Mg, Al) are very reactive.

  • These metals are never found in nature as free elements.

• Moderately Reactive Metals:

  • Metals in the middle of the activity series (Zn, Fe, Pb) are moderately reactive.

  • These metals are found in the earth’s crust mainly as oxides, sulphides, or carbonates.

• Ores and Oxides:

  • Many metal ores are oxides because oxygen is a highly reactive and abundant element on Earth.

• Categories of Metals Based on Reactivity:

  • Metals of low reactivity

  • Metals of medium reactivity

  • Metals of high reactivity

• Extraction Techniques:

  • Different techniques are used for extracting metals in each category:

    • Reduction using carbon

    • Electrolysis

    • Found in native state

• Enrichment of Ores:

  • Ores mined from the earth often contain impurities like soil, sand, etc., called gangue.

  • Gangue must be removed before metal extraction.

The correct answer is Magnesium.

Key Points

• In the reactivity series, metals are arranged based on their ability to lose electrons and form positive ions.
• Magnesium is placed between aluminium and zinc in the reactivity series due to its chemical properties and reactivity.
• Magnesium is more reactive than aluminium because it loses electrons more easily to form a cation but is less reactive than zinc.
• The reactivity of a metal is determined by its tendency to participate in oxidation-reduction reactions.
• Magnesium is a highly reactive metal that reacts with oxygen to form magnesium oxide (MgO) and with acids to release hydrogen gas.
• It is widely used in applications such as alloys, fireworks, and medicines due to its reactivity and lightweight nature.
• The placement of magnesium in the series makes it an important reference point for understanding the behavior of metals in displacement reactions.

 Additional Information

• Iron
  • Iron is less reactive than magnesium and zinc, which is why it is placed lower in the reactivity series.
  • It is widely used in industries for the production of steel and alloys.
  • Iron reacts with oxygen in moist air to form rust (iron oxide), a process known as corrosion.
• Copper
  • Copper is a low-reactivity metal and is placed much lower in the reactivity series compared to magnesium.
  • It is an excellent conductor of electricity and is commonly used in electrical wiring and electronics.
  • Copper does not react with water or dilute acids under normal conditions.
• Carbon
  • Although carbon is not a metal, it plays a significant role in the reactivity series as a reference for the reduction of metal oxides.
  • It is used in the extraction of metals from their ores through the process of reduction.
  • Carbon is also an essential element in the form of graphite and diamond, which have unique physical properties.

The correct answer is Both A and R are true, and R is not a correct explanation of A.

Key Points

• Metals generally possess a lustrous appearance, meaning they are shiny, which is one of their defining physical properties.
• Metals are known to be excellent conductors of heat and electricity due to the presence of free electrons that move freely through the lattice structure.
• Non-metals, on the other hand, lack lustre and are typically poor conductors of heat and electricity because they do not have free electrons available for conduction.
• The Assertion (A) that "Metals generally have a lustrous appearance and are good conductors of heat and electricity" is true.
• The Reason (R) that "Non-metals lack lustre and are usually poor conductors of heat and electricity" is also true.
• The relationship between metals and non-metals is based on their atomic structure, which defines their distinct physical and chemical properties.
• Examples of metals include copper, silver, and gold, which are highly lustrous and conductive. Examples of non-metals include carbon, sulfur, and phosphorus, which are dull and non-conductive.

Additional Information

Properties of metal-

• high melting points.
• good conductors of electricity.
• good conductors of heat.
• high density.
• malleability
• ductility 

Properties of non-metal-

• non-metals are neither malleable nor ductile; they are brittle.

The correct answer is Only II and IV.

Key Points

• Statement II: Iron can replace copper from copper sulphate solution because iron is more reactive than copper. This is based on the reactivity series of metals.
• Statement IV: Sodium is a highly reactive alkali metal that is soft and can be easily cut with a knife due to its low density and metallic bonding.
• Statement I is incorrect: All metals do not have the same reactivity. The reactivity of metals varies and is arranged in the reactivity series.
• Statement III is incorrect: Copper cannot replace iron from ferrous sulphate solution because copper is less reactive than iron.

Additional Information

• Reactivity Series: A list of metals arranged in order of their decreasing reactivity. Highly reactive metals like sodium and potassium are at the top, while less reactive metals like gold and silver are at the bottom.
• Displacement Reaction: A chemical reaction in which a more reactive metal displaces a less reactive metal from its compound (e.g., iron displaces copper from copper sulphate).
• Properties of Sodium: Sodium is an alkali metal with low melting point and density. It reacts vigorously with water and oxygen, and it is so soft that it can be cut with a knife.
• Metal Reactivity: Reactivity of a metal determines its ability to lose electrons and form positive ions. Highly reactive metals like alkali metals react easily, while noble metals like gold and platinum are least reactive.
• Chemical Behavior of Copper: Copper is a less reactive metal and cannot displace more reactive metals such as iron from their compounds.

The correct answer is Zinc.Key Points

• Zinc is more reactive than copper.
• Zinc is more reactive than copper metal and so it can displace copper from copper sulphate solution.
• Zinc displaces the metals present below it in the series.

Additional Information

• Reactivity of an element decreases from top to bottom in the given reactivity series.
  • Potassium (K) 
  • Sodium (Na) 
  • Calcium (Ca)
  • Magnesium (Mg) 
  • Aluminium (Al) 
  • Zinc (Zn) 
  • Carbon (C) 
  • Iron (Fe) 
  • Lead (Pb) 
  • Hydrogen (H) 
  • Copper (Cu) 
  • Silver (Ag)
  • Gold (Au)
• Platinum is known as a noble metal due to its remarkable resistance to corrosion and oxidation. It is one of the least reactive metals, which means that it does not easily react with other elements or compounds under normal conditions. This property makes platinum highly valuable for use in a variety of applications, such as in electronics, jewelry, and catalytic converters in vehicles.

The correct answer is Sodium.

Key Points

• Sodium reacts vigorously with cold water to produce sodium hydroxide (NaOH) and hydrogen gas (H₂).
• The reaction is highly exothermic, meaning it releases a significant amount of heat.
• Because of its vigorous reaction with water, sodium is stored in kerosene or mineral oil to prevent it from coming into contact with moisture.
• In the reactivity series of metals, sodium is placed higher up, indicating its high reactivity.

Additional Information

• Reactivity Series: This is a series of metals arranged in order of decreasing reactivity. The most reactive metals are at the top, and the least reactive are at the bottom.
• Exothermic Reaction: A chemical reaction that releases energy by light or heat. It is the opposite of an endothermic reaction.
• Sodium Hydroxide (NaOH): Also known as caustic soda or lye, it is a highly caustic metallic base and alkali salt used in many industrial processes.
• Hydrogen Gas (H₂): The lightest and most abundant chemical substance in the universe, hydrogen gas is highly flammable and is used in various industrial applications.
• Storage of Sodium: Due to its high reactivity with water and air, sodium is stored under oil to prevent accidental reactions.

The correct answer is Electrolytic refining.

Key Points

• Electrolytic refining is a method used to purify impure metals by using electrolysis.
• In this process, the impure metal is made the anode, and a pure metal strip is made the cathode.
• An electrolyte solution containing the metal ions is used to facilitate the transfer of metal ions from the anode to the cathode.
• As a result, the pure metal is deposited on the cathode, while impurities either fall off as anode mud or remain in the solution.
• This method is commonly used for refining metals like copper, nickel, lead, and zinc.

Additional Information

• Electrolysis is the process of using an electric current to drive a non-spontaneous chemical reaction.
• In electrolytic refining, the energy supplied by the electric current helps in the separation of pure metal from its impurities.
• Anode refers to the electrode where oxidation occurs, while the cathode refers to the electrode where reduction occurs.
• Anode mud is the insoluble impurities that collect at the bottom of the electrolytic cell during the refining process.
• This method ensures high purity levels of the refined metal, often exceeding 99.9% purity.

The correct answer is Salt and hydrogen gas.

Key Points

• When acids react with metals, they produce a salt and hydrogen gas.
• This is a typical single displacement reaction where the metal displaces hydrogen from the acid.
• For example, when zinc (Zn) reacts with hydrochloric acid (HCl), it forms zinc chloride (ZnCl₂) and hydrogen gas (H₂).
• The general equation for this type of reaction is: Metal + Acid → Salt + Hydrogen gas.
• Common metals that react with acids include zinc, magnesium, and iron.

Additional Information

• Oxidation-Reduction Reaction: In the reaction between acids and metals, the metal undergoes oxidation (loses electrons) and hydrogen ions (H⁺) from the acid are reduced (gain electrons).
• Reactivity Series: Not all metals react with acids. The reactivity series of metals determines which metals will react with acids to produce hydrogen gas.
• Safety Precautions: The reaction between metals and acids can be vigorous and produce hydrogen gas, which is highly flammable. Proper safety measures should be taken.
• Applications: This type of reaction is utilized in various industrial processes including the production of hydrogen gas and in metal refining.

The correct answer is Mercury.

Key Points

• Mercury is the only metal that is liquid at room temperature.
• The chemical symbol for mercury is Hg, derived from its Greek name, hydrargyrum, meaning "water-silver".
• Mercury is a heavy, silvery-white metal and is known for its high density and ability to form amalgams with other metals.
• It has a melting point of -38.83 degrees Celsius and a boiling point of 356.73 degrees Celsius.
• Mercury is used in various applications such as thermometers, barometers, and dental amalgams, though its use has decreased due to toxicity concerns.

Additional Information

• Toxicity of Mercury
  • Mercury is highly toxic, especially in its organic form (methylmercury).
  • Exposure to mercury can affect the nervous system, digestive system, and immune system, and can be fatal.
  • Minamata disease is a neurological syndrome caused by severe mercury poisoning.
  • Due to its toxicity, the use and disposal of mercury are strictly regulated.
• Mercury in the Environment
  • Mercury can be released into the environment through industrial processes, such as coal burning and mining.
  • Once in the environment, mercury can be converted to methylmercury by microbial activity in water bodies.
  • Methylmercury accumulates in fish and shellfish, leading to bioaccumulation and biomagnification up the food chain.
  • Consuming contaminated fish is a primary source of mercury exposure for humans.
• Handling and Safety
  • Due to its toxicity, mercury must be handled with care using appropriate safety measures, such as gloves and fume hoods.
  • Spills should be cleaned up immediately using specialized kits designed for mercury spillages.
  • Disposal of mercury requires adherence to hazardous waste regulations to prevent environmental contamination.
  • Mercury-free alternatives are increasingly being used in medical and industrial applications to mitigate risks.

The Correct answer is All metals are equally reactive.

Key Points

• Not all metals have the same level of reactivity. Metals differ in their ability to react with other substances.
• The reactivity series is a list of metals arranged in order of their reactivity, from highest to lowest. For instance, potassium and sodium are highly reactive, while gold and silver are much less reactive.
• Potassium is known to be more reactive than gold, which is why it is never found in its free state in nature.
• Silver is less reactive than sodium, meaning it does not react as easily or vigorously with other elements or compounds.
• The differences in reactivity among metals are due to their varying atomic structures and the energy required to remove an electron to form a positive ion.

 Additional Information

• Potassium
  • Potassium is an extremely reactive metal and is placed high in the reactivity series.
  • It reacts vigorously with water and even with moisture in the air, often producing a flame.
  • Because of its high reactivity, potassium is stored under mineral oil to prevent it from reacting with atmospheric moisture and oxygen.
• Gold
  • Gold is a noble metal, meaning it is highly resistant to corrosion and oxidation.
  • This low reactivity makes gold ideal for use in jewelry and electronics.
  • Gold does not react with most chemicals, and it is only attacked by a mixture of nitric acid and hydrochloric acid, known as aqua regia.
• Silver
  • Silver is less reactive than metals like sodium and potassium but more reactive than gold.
  • It tarnishes when exposed to air due to the formation of silver sulfide from the reaction with sulfur compounds.
  • Silver is widely used in jewelry, cutlery, and electrical contacts due to its relative reactivity and high conductivity.

The correct answer is pure gold.

Key Points

• Gold purity is measured in karats, with 24 karats being 100% pure gold.
• Common gold purities include 24K, 22K, 18K, and 14K, where K stands for karats.
• The highest purity for gold is 24 karats, equating to 99.9% gold.

Additional Information

• Karat System: The karat system is used to denote the purity of gold, with 24 karats representing pure gold.
• Alloying: Gold is often alloyed with other metals such as copper or silver to increase its hardness and durability.
• Gold Standards: Different countries have various standards for gold purity, commonly 22K in India and 18K in Europe.
• Weight vs. Purity: "Carat" (with a "c") is also a unit of weight used for gemstones, distinct from "karat" (with a "k") for gold purity.
• Gold Uses: Pure gold (24K) is too soft for everyday wear, hence lower karat gold is used for jewelry to ensure durability.

The Correct answer is ductility.

Key Points

• Ductility refers to the ability of a material to be stretched into a wire without breaking.
• This property is commonly associated with metals, allowing them to be drawn into thin wires.
• Gold and silver are examples of highly ductile metals.
• Ductility is a key factor in industrial applications, especially in electrical wiring and metal forming.
• It is measured by the material’s ability to undergo significant plastic deformation before rupture.
• Materials with high ductility can absorb significant stress and strain, making them ideal for construction and manufacturing.

 Additional Information

• Hardness
  • Hardness is the measure of a material's resistance to deformation, particularly indentation or scratching.
  • It is often assessed using tests like the Mohs hardness test or the Rockwell hardness test.
  • Materials like diamonds are known for their high hardness.
• Malleability
  • Malleability is the ability of a material to be hammered or rolled into thin sheets without breaking.
  • Examples of malleable materials include gold and aluminum.
  • This property is crucial for applications in metalworking and manufacturing.
• Brittleness
  • Brittleness refers to the tendency of a material to break or shatter without significant deformation when under stress.
  • Brittle materials, like glass and ceramics, have low ductility and malleability.

The correct answer is Option 4.

Key Points

• Reactivity Series: Zinc is more reactive than copper, and lead is also more reactive than copper. This follows the order of reactivity in the metal reactivity series.
• Zinc Reactivity: Zinc can displace copper from its compounds due to its higher reactivity.
• Lead Reactivity: Lead, although less reactive than zinc, is still more reactive than copper.
• Iron and Copper Sulphate Reaction: An iron nail dipped in copper sulphate solution will turn brownish-red due to the deposition of copper, not yellow.

Additional Information

• Metal Reactivity Series: This series ranks metals from highest to lowest reactivity. Elements like potassium and sodium are at the top, while gold and platinum are at the bottom.
• Displacement Reactions: More reactive metals can displace less reactive metals from their compounds in aqueous solutions.
• Copper Sulphate Solution: It is a blue solution commonly used in school experiments to demonstrate displacement reactions.
• Iron and Copper Reaction: When iron reacts with copper sulphate, iron displaces copper, forming iron sulphate and copper metal, which deposits on the iron surface.
• Color Changes in Reactions: The color change in chemical reactions involving transition metals can often indicate the formation of different compounds or the deposition of metals.

The correct answer is Magnesium.

Key Points

• In the reactivity series, metals are arranged based on their ability to lose electrons and form positive ions.
• Magnesium is placed between aluminium and zinc in the reactivity series due to its chemical properties and reactivity.
• Magnesium is more reactive than aluminium because it loses electrons more easily to form a cation but is less reactive than zinc.
• The reactivity of a metal is determined by its tendency to participate in oxidation-reduction reactions.
• Magnesium is a highly reactive metal that reacts with oxygen to form magnesium oxide (MgO) and with acids to release hydrogen gas.
• It is widely used in applications such as alloys, fireworks, and medicines due to its reactivity and lightweight nature.
• The placement of magnesium in the series makes it an important reference point for understanding the behavior of metals in displacement reactions.

 Additional Information

• Iron
  • Iron is less reactive than magnesium and zinc, which is why it is placed lower in the reactivity series.
  • It is widely used in industries for the production of steel and alloys.
  • Iron reacts with oxygen in moist air to form rust (iron oxide), a process known as corrosion.
• Copper
  • Copper is a low-reactivity metal and is placed much lower in the reactivity series compared to magnesium.
  • It is an excellent conductor of electricity and is commonly used in electrical wiring and electronics.
  • Copper does not react with water or dilute acids under normal conditions.
• Carbon
  • Although carbon is not a metal, it plays a significant role in the reactivity series as a reference for the reduction of metal oxides.
  • It is used in the extraction of metals from their ores through the process of reduction.
  • Carbon is also an essential element in the form of graphite and diamond, which have unique physical properties.