Metal MCQ Quiz in मल्याळम - Objective Question with Answer for Metal - സൗജന്യ PDF ഡൗൺലോഡ് ചെയ്യുക

The correct answer is Option 4.

Key Points

• Option 4 states that "Certain materials called semiconductors by definition have zero resistivity or infinite conductivity," which is incorrect.
• Semiconductors have a moderate level of conductivity, which is between that of insulators and conductors.
• Semiconductors like silicon and germanium do not have zero resistivity; their resistivity decreases with increasing temperature.
• In semiconductors, conductivity can be controlled by adding impurities, a process known as doping.

Additional Information

• Conductors
  • Materials that allow the flow of electric current with minimal resistance.
  • Examples include metals like copper, silver, and aluminum.
• Insulators
  • Substances with very low conductivity, preventing the flow of electric current.
  • Examples include glass, ceramics, and plastics.
• Semiconductors
  • Materials with conductivity between conductors and insulators.
  • Used in electronic devices like transistors and diodes.
  • Examples include silicon and germanium.
• Doping
  • The process of adding impurities to semiconductors to change their electrical properties.
  • Increases the number of charge carriers in the material.

The correct answer is 3) Both statements I and II are correct.

Key Points

• Non-metallic oxides such as CO₂ and SO₂ react with bases to form salt and water, demonstrating their acidic nature.
• Statement I is correct as it describes the neutralization reaction between a non-metallic oxide and a base.
• Statement II is correct as non-metallic oxides are indeed acidic in nature, meaning they react with bases.
• Examples include CO₂ reacting with NaOH to form Na₂CO₃ (sodium carbonate) and water.

Additional Information

• Acid-Base Reactions:
  • Acid-base reactions involve the transfer of protons (H⁺) from the acid to the base.
  • These reactions result in the formation of water and a salt.
• Examples of Non-Metallic Oxides:
  • Carbon dioxide (CO₂), sulfur dioxide (SO₂), and nitrogen dioxide (NO₂) are common non-metallic oxides.
  • These oxides typically react with water to form acids.
• Neutralization Reactions:
  • In a neutralization reaction, an acid and a base react to form water and a salt.
  • This type of reaction is essential in various industrial and biological processes.
• Properties of Acids and Bases:
  • Acids have a sour taste and can turn blue litmus paper red.
  • Bases have a bitter taste and can turn red litmus paper blue.

The correct answer is Nitrogen.

Key Points

• Nitrogen is a non-metallic element and is represented by the symbol N.
• It is the most abundant gas in Earth's atmosphere, making up approximately 78% of the air by volume.
• Nitrogen belongs to Group 15 (the Nitrogen family) in the periodic table and exhibits non-metallic properties due to its high electronegativity and inability to conduct electricity.
• It is essential for life, playing a critical role in the formation of amino acids, proteins, and nucleic acids in living organisms.
• Unlike metals, nitrogen does not possess metallic luster, is brittle in its solid form, and does not conduct heat or electricity.

Additional Information

• Non-metals:
  • Non-metals are elements that generally lack metallic properties like ductility, malleability, and electrical conductivity.
  • Examples of non-metals include oxygen, nitrogen, carbon, sulfur, and phosphorus.
  • They are usually poor conductors of heat and electricity and are often found in gaseous, liquid, or brittle solid forms.
• Metallic Elements:
  • Metals like rubidium, copper, and silver (mentioned in the options) are excellent conductors of heat and electricity.
  • These elements are malleable, ductile, and possess metallic luster.
• Nitrogen Cycle:
  • Nitrogen is a key component of the nitrogen cycle, which involves processes like nitrogen fixation, nitrification, and denitrification.
  • These processes ensure the availability of nitrogen in forms usable by plants and animals.
• Group 15 Elements:
  • Group 15 elements in the periodic table are also called the Nitrogen family and include nitrogen, phosphorus, arsenic, antimony, and bismuth.
  • Non-metals dominate the top of the group, while metallic characteristics increase as you move down the group.

The correct answer is Iron.

Key Points

• Iron does not react with cold or hot water because it is relatively less reactive compared to other metals like sodium, calcium, and magnesium.
• Iron reacts only with steam at high temperatures, forming iron oxide (Fe3O4) and releasing hydrogen gas.
• Metals like sodium and calcium are highly reactive and readily react with cold water, producing hydrogen gas and metal hydroxides.
• Magnesium reacts with hot water slowly but does not react with cold water significantly.
• Iron's low reactivity with water makes it suitable for many applications, including construction and manufacturing industries.

Additional Information

• Reactivity Series: Metals are arranged based on their reactivity, with potassium and sodium at the top and gold at the bottom. Iron is placed below magnesium in the series, indicating its lower reactivity.
• Reaction of Metals with Water: Highly reactive metals like sodium and potassium react explosively with water, while less reactive metals like iron require higher temperatures (steam) for reaction.
• Iron Oxides: Iron reacts with oxygen and steam to form iron oxides, such as Fe3O4 (magnetite), which are used in industrial processes.
• Applications of Iron: Due to its stability and resistance to water, iron is widely used in construction, transportation, and manufacturing tools and machinery.
• Steam Reaction: When iron reacts with steam, the chemical equation is: 3Fe + 4H2O → Fe3O4 + 4H2, showcasing its limited reactivity under specific conditions.

The Correct answer is Bronze.

Key Points

• Bronze is an alloy primarily made of copper (Cu) and tin (Sn). The typical ratio used is approximately 88% copper and 12% tin.
• This alloy has been in use since the Bronze Age (around 3300 BCE to 1200 BCE), marking a significant advancement in human technology.
• Bronze is known for its strength, durability, and resistance to corrosion, making it suitable for creating tools, weapons, and sculptures.
• The addition of tin to copper reduces its melting point and increases its hardness, which are crucial properties for crafting robust materials.
• It is widely used in the manufacturing of statues, coins, musical instruments, and bearings.
• Some historical artifacts, such as the famous Bronze sculptures from ancient civilizations, showcase the significance of this alloy in early societies.

 Additional Information

• Solder
  • Solder is another alloy, commonly composed of tin (Sn) and lead (Pb). It is primarily used in electronics and plumbing for joining metal components.
  • Solder has a low melting point, making it ideal for creating secure connections without damaging sensitive materials.
• Gold
  • Gold is a pure metal rather than an alloy. It is known for its malleability, ductility, and resistance to tarnish.
  • Gold is widely used in jewelry, electronics, and financial reserves.
• Brass
  • Brass is another alloy, made of copper (Cu) and zinc (Zn).
  • It is known for its golden appearance and is commonly used in decorative items, musical instruments, and plumbing fittings.

The correct answer is Magnesium.

Key Points

• Magnesium is a metal that does not react with cold water.
• It only reacts with hot water or steam to produce magnesium hydroxide and hydrogen gas.
• The reaction of magnesium with water is much slower compared to other metals like potassium, sodium, and calcium.
• Magnesium forms a protective layer of magnesium hydroxide on its surface, which prevents further reaction with water.
• This characteristic makes magnesium less reactive with cold water.

 Additional Information

• Potassium
  • Potassium reacts very vigorously with cold water, producing potassium hydroxide and hydrogen gas.
  • The reaction is exothermic and can ignite the hydrogen gas produced.
• Sodium
  • Sodium also reacts vigorously with cold water, forming sodium hydroxide and hydrogen gas.
  • Similar to potassium, the reaction is exothermic and can ignite the hydrogen gas.
• Calcium
  • Calcium reacts with cold water to produce calcium hydroxide and hydrogen gas, but the reaction is less vigorous compared to potassium and sodium.

The correct answer is Magnesium.

Key Points

• Magnesium is higher in the reactivity series compared to Iron, Aluminium, and Zinc.
• When magnesium reacts with sulphuric acid, it displaces hydrogen gas rapidly due to its high reactivity.
• The reactivity series of metals places magnesium above zinc, iron, and aluminium, making it more reactive.
• Hydrogen gas bubbles will form at a faster rate when magnesium is used in the reaction with sulphuric acid.

Additional Information

• Reactivity Series: The reactivity series is a list of metals arranged in order of decreasing reactivity to displace hydrogen from acids and water.
• Hydrogen Displacement: Metals higher in the reactivity series can displace hydrogen gas from acids faster than those lower in the series.
• Magnesium (Mg): A lightweight, silvery metal that reacts vigorously with acids to produce hydrogen gas.
• Sulphuric Acid (H₂SO₄): A strong acid commonly used in chemical reactions to test the reactivity of metals.
• Safety Precautions: When performing reactions with acids, appropriate safety measures like wearing gloves and goggles should be taken to prevent harm.

The Correct answer is Potassium.

Key Points

• Potassium is the most reactive metal in the reactivity series.
• It is placed at the top because of its high reactivity with oxygen, water, and acids.
• Potassium reacts vigorously with water to form potassium hydroxide and hydrogen gas.
• This metal is stored under oil to prevent it from reacting with moisture in the air.
• Potassium is used in fertilizers, soaps, and detergents due to its high reactivity.
• It is also essential for plant growth, playing a key role in the functioning of plant cells.

 Additional Information

• Copper
  • Copper is a less reactive metal compared to potassium.
  • It is widely used in electrical wiring and electronics due to its high electrical conductivity.
  • Copper is also used in plumbing and roofing materials.
• Iron
  • Iron is more reactive than copper but less reactive than potassium.
  • It is a major component in steel production.
  • Iron is used in construction, transportation, and various industrial applications.
• Silver
  • Silver is one of the least reactive metals.
  • It is highly valued for its conductivity and is used in jewelry and currency.
  • Silver has various industrial applications, including in photography and electronics.

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.

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.