Elements in the periodic table are classified into metals, non-metals, and metalloids based on physical and chemical properties. Metals exhibit high electrical conductivity, thermal conductivity, malleability, ductility, and electropositive character, forming basic oxides. The reactivity series arranges metals in descending order of chemical reactivity: Potassium > Sodium > Calcium > Magnesium > Aluminium > Zinc > Iron > Lead > [Hydrogen] > Copper > Mercury > Silver > Gold. Highly electropositive metals are extracted via molten salt electrolysis, whereas moderate reactivity metals undergo concentration (e.g., froth floatation for sulphide ores), followed by calcination (heating in limited air for carbonates) or roasting (heating in excess oxygen for sulphides) prior to carbon or aluminothermic reduction. Alloys are homogeneous solid solutions engineered for enhanced tensile strength and corrosion resistance. Standard alloys include Brass (copper and zinc), Bronze (copper and tin), Stainless Steel (iron, chromium, nickel, and carbon), Solder (lead and tin), and Duralumin (aluminium, copper, magnesium, and manganese). Amalgams represent alloys formed specifically with mercury, while galvanization coats sacrificial zinc onto iron to prevent oxidative rusting.
High-yield conceptual summaries for competitive exams and rapid revision.
The metal reactivity series places Potassium and Sodium at the most reactive apex and Gold and Platinum at the unreactive base.
Sulphide ores are concentrated by froth floatation and converted to oxides via roasting, whereas carbonate ores undergo calcination in limited air.
Brass is a binary alloy composed of Copper and Zinc, while Bronze is primarily composed of Copper and Tin.
Stainless Steel combines Iron with at least 10.5% Chromium, Nickel, and Carbon to form a corrosion-resistant passive chromium oxide layer.
Galvanization prevents iron corrosion by applying a protective sacrificial coating of metallic zinc via hot-dip or electroplating processes.
Showing 25 Curated Questions66 Total in Bank
1ID: GK-OCEN-00012
easyDeep Ocean Mission & Submersibles
What high-strength metallic alloy material is utilized to fabricate the 2.1-metre internal diameter spherical personnel hull of MATSYA 6000 to endure 600 bar hydrostatic pressure?
Verified Explanation
The spherical pressure hull of the MATSYA 6000 manned submersible is engineered using Titanium alloy (Ti-6Al-4V) due to its exceptional strength-to-weight ratio, high fracture toughness, and superior corrosion resistance at 6,000 metres ocean depth.
2ID: GK-EPIG-00357
mediumCopper-Plate Charters & Ancient Indian Coinage
Unlike the northern empires that minted gold, the Satavahanas of the Deccan issued extensive base-metal coinage manufactured primarily from lead, copper, and which unique alloy?
Verified Explanation
The Satavahana dynasty issued large volumes of coinage in lead and 'potin' (a multi-metal base alloy consisting of copper, lead, tin, and zinc), with symbols such as the Ujjain symbol, Chaitya (three-peaked hill), elephant, and lion.
3ID: GK-EPIG-00480
mediumCopper-Plate Charters & Ancient Indian Coinage
Unlike north Indian empires which minted vast quantities of gold, which distinctive base metal alloy (an alloy of copper, lead, tin, and zinc) and pure lead were predominantly used by the Satavahana dynasty for daily currency across the Deccan?
Verified Explanation
The Satavahanas minted millions of lead and potin (an alloy of copper and high-lead content) coins bearing symbols like the Ujjain symbol, Chaitya/hill, ship with double masts, elephant, and lion, perfectly suited for the regional Deccan trade economy.
4ID: GK-CITY-00110
hardTextile, Leather, Diamond & Steel Capitals of India
Which historic town in Bidar district of Karnataka is globally celebrated for its 14th-century Bahmani metal inlay craft where blackened zinc-copper alloy is inlaid with pure silver wire?
Verified Explanation
Bidar is world-famous for GI-tagged 'Bidriware', a distinctive metal handicraft developed during the Bahmani Sultanate using soil from Bidar Fort to oxidize and blacken the silver-inlaid zinc alloy.
5ID: GK-CITY-00251
easyTextile, Leather, Diamond & Steel Capitals of India
Which heritage village in the Pathanamthitta district of Kerala is world-famous for its GI-tagged handmade front-surface metal alloy mirrors ('Aranmula Kannadi') cast from a copper-tin speculum alloy?
Verified Explanation
Aranmula Kannadi is an extraordinary front-surface reflecting mirror crafted exclusively by traditional master metallurgists in Aranmula village, Kerala, using a secret metallurgical alloy of copper and tin rather than silvered glass.
6ID: GK-CITY-00573
mediumTextile, Leather, Diamond & Steel Capitals of India
Which historic village in Pathanamthitta district of Kerala is world-renowned for its GI-tagged, handmade front-surface metal-alloy mirrors?
Verified Explanation
Aranmula is celebrated worldwide for the 'Aranmula Kannadi', a handmade metal-alloy mirror (copper and tin) with front-surface reflection, crafted exclusively by a traditional artisan family guild.
7ID: GK-ART-00432
mediumIndian Paintings & Handicrafts
Bidriware, the traditional handicraft metalwork featuring pure silver inlay designs on a blackened zinc-copper alloy, originated in which historic city?
Verified Explanation
Bidriware originated during the 14th century Bahmani Sultanate rule in Bidar, Karnataka, where inlaid silver wire is embedded on blackened zinc-copper alloy treated with local soil.
8ID: GK-ART-00563
mediumIndian Paintings & Handicrafts
Bidriware, an ancient handicraft metal inlay art made from an alloy of zinc and copper inlaid with pure silver sheets, originated in:
Verified Explanation
Bidriware was developed in the 14th century in Bidar under the Bahmani Sultanate, known for its distinctive blackened zinc alloy contrasting with inlaid pure silver wires.
9ID: GK-ART-00731
hardPainting Traditions, Folk Crafts & Textiles
In the production of Bidriware handicrafts, the zinc-copper alloy base inlaid with pure silver is chemically blackened using a paste containing soil obtained from?
Verified Explanation
Bidriware originated in Bidar (Karnataka) under the Bahmani Sultanate. To impart its jet-black patina, artisans boil the silver-inlaid zinc-copper alloy object in a chemical solution of ammonium chloride and specialized nitrate-rich soil gathered exclusively from unexposed areas inside the historic Bidar Fort.
10ID: GK-ART-00824
mediumPainting Traditions, Folk Crafts & Textiles
'Bidriware', a 500-year-old GI-tagged metalcraft where pure silver wire is inlaid into a blackened alloy of zinc and copper treated with specialized soil from the local fort, originated in which historic town?
Verified Explanation
Bidriware is an ancient metal inlay craft developed in the 14th century during the Bahmani Sultanate in Bidar, Karnataka. Artisans cast objects from an alloy of zinc (over 90%) and copper, engrave intricate geometric or floral designs, inlay pure silver wire or sheet, and coat the piece with a paste containing soil collected from the unexposed areas of Bidar Fort, which turns the base alloy velvety black while leaving the silver lustrous.
11ID: GK-ART-00826
mediumPainting Traditions, Folk Crafts & Textiles
The 'Aranmula Kannadi', a GI-tagged metal-alloy mirror that eliminates secondary reflections because it is a front-surface reflective mirror, is handcrafted exclusively in which state?
Verified Explanation
Aranmula Kannadi is a handmade metal-alloy mirror produced in the village of Aranmula in Pathanamthitta district, Kerala. Unlike conventional glass mirrors coated with silver on the back, it is cast from a secret metallurgic copper-tin alloy polished for days, resulting in a front-surface mirror that reflects light directly without secondary refraction or chromatic distortion.
12ID: GK-ART-01023
easyPainting Traditions, Folk Crafts & Textiles
The distinctive handicraft 'Bidriware', developed under the Bahmani Sultanate in Karnataka, involves inlaying pure silver onto an alloy composed primarily of which metal, blackened with soil from Bidar Fort?
Verified Explanation
Bidriware is cast from a base alloy of zinc and copper (in approximately 16:1 ratio). After pure silver wire or sheet is inlaid into engraved grooves, the object is permanently blackened using an ammonium-rich soil collected from Bidar Fort.
13ID: GK-OCEN-00132
easyDeep Ocean Mission & Submersibles
The human crew capsule of India's deep submersible 'MATSYA 6000' is engineered as a spherical pressure hull made primarily from which high-strength metal alloy?
Verified Explanation
The personnel sphere of MATSYA 6000 has an internal diameter of 2.1 metres and an 80 mm wall thickness, constructed from ultra-high-strength Titanium alloy (Ti-6Al-4V) to safely withstand hydrostatic pressures exceeding 600 bar (60 MPa) at 6,000 metres ocean depth.
What high-strength alloy is used to fabricate the 2.1-metre diameter spherical human crew capsule of India's MATSYA 6000 deep submersible?
Verified Explanation
The human-occupied pressure hull of MATSYA 6000 is manufactured from high-strength titanium alloy (Ti-6Al-4V). With a diameter of 2.1 metres and an 80 mm wall thickness, the sphere accommodates three crew members while withstanding immense hydrostatic pressures of 600 bar at a depth of 6,000 metres.
15ID: GK-SCIT-00439
mediumNanotechnology & Materials Science
What shape memory alloy (SMA), composed of roughly equiatomic nickel and titanium, exhibits superelasticity and the ability to return to its original shape upon heating?
Verified Explanation
Nitinol (Nickel Titanium Naval Ordnance Laboratory) is a shape memory alloy that undergoes reversible martensitic phase transformation upon thermal cycling.
16ID: GK-SCIT-00672
mediumNuclear Energy & Reactor Technology
In Indian Pressurized Heavy Water Reactors (PHWRs), the fuel bundles are housed inside high-pressure coolant channels manufactured from which alloy?
Verified Explanation
Pressure tubes in Indian PHWRs operate at ~300 °C and 10 MPa and are made of a Zirconium-2.5% Niobium (Zr-2.5%Nb) alloy. Zirconium alloys provide a low thermal neutron capture cross-section (~0.18 barns), high corrosion resistance in hot heavy water, and mechanical creep resistance.
17ID: GK-SCIT-00983
hardNuclear Energy & Reactor Technology
What metallurgical modification is applied in Indian Fast Reactor structural materials (such as modified Alloy D9 stainless steel) to prevent void swelling under extreme fast neutron fluence?
Verified Explanation
Under intense fast neutron irradiation (>100 dpa), atomic displacements create vacancies that aggregate into microscopic voids, causing dimensional swelling and embrittlement. Titanium-modified austenitic stainless steel (Alloy D9) with controlled silicon and carbon contents and ~20% cold working forms nanoscale TiC precipitates that serve as sinks for point defects, suppressing void nucleation in fast reactor core claddings.
18ID: GK-CITY-00174
hardTextile, Leather, Diamond & Steel Capitals of India
Which town in the Bidar district of Karnataka is globally famed for its 14th-century Bahmani-era metal craft involving inlaid silver and gold on blackened zinc-copper alloy?
Verified Explanation
Bidar is celebrated worldwide for 'Bidriware', a distinctive metal handicraft developed during the Bahmani Sultanate, bearing a GI registration.
19ID: GK-CITY-00463
hardTextile, Leather, Diamond & Steel Capitals of India
Which city in Tamil Nadu, situated at the base of the Shevaroy Hills, is renowned as the 'Steel City' of Tamil Nadu for its special alloy and stainless steel plant, as well as the 'Mango City'?
Verified Explanation
Salem is famous for SAIL's Salem Steel Plant (specializing in world-class cold-rolled stainless steel) and for its high-grade Malgoa and Salem Bangalora mango varieties.
20ID: GK-CITY-00512
mediumTextile, Leather, Diamond & Steel Capitals of India
Which historic city in northern Karnataka is the global home of 'Bidriware', a 14th-century metal handicraft featuring pure silver inlay on blackened zinc-copper alloy?
Verified Explanation
Bidriware originated in Bidar during the Bahmani Sultanate; its striking contrast of pure silver inlaid on blackened metal is achieved using soil uniquely sourced from the unlit depths of Bidar Fort.
21ID: GK-DTECH-00186
hardSubmarines, Aircraft Carriers & Naval Systems
Which high-strength, low-alloy specialized micro-alloyed naval steel developed jointly by DMRL (DRDO) and SAIL is used to construct the hulls of Indian aircraft carriers and warships?
Verified Explanation
DMR-249A and DMR-249B are specialized micro-alloyed naval grade steels developed by DMRL (DRDO) and manufactured by Steel Authority of India Limited (SAIL). They possess exceptional yield strength, crack resistance, and high-impact toughness at sub-zero temperatures.
Which high-tensile, low-alloy specialty steel grade was indigenously developed by DMRL/DRDO and manufactured by the Steel Authority of India (SAIL) for building the hulls of INS Vikrant and modern Indian warships?
Verified Explanation
DMR 249A (and its higher-strength variant DMR 249B) is an indigenous low-carbon micro-alloyed high-tensile warship structural steel developed by DRDO's Defence Metallurgical Research Laboratory (DMRL) and produced by SAIL's Bhilai, Bokaro, and Rourkela steel plants, ending India's dependence on imported warship steel.
23ID: GK-ART-00112
mediumPaintings Handicrafts
The "Bidriware" metal handicraft, celebrated for striking silver inlay work on a blackened zinc-copper alloy base, originated in which historic town?
Verified Explanation
Bidriware developed in the 14th century in Bidar; the metal is blackened using soil from the historic Bidar Fort containing special chemicals.
24ID: GK-ART-00510
mediumIndian Paintings & Handicrafts
Bidriware, a metal handicraft inlaid with pure silver wires on a blackened alloy of zinc and copper, originated in which historic town?
Verified Explanation
Bidriware originated in the 14th century in Bidar under the Bahmani Sultanate and holds a Geographical Indication (GI) tag.
25ID: GK-MNRL-00083
mediumCritical Minerals Mission, Lithium & REEs
Which high-performance permanent magnet type, made from an alloy of rare earth and transition metals, is preferred in military aircraft, missiles, and high-temperature actuators because it retains magnetism above 300°C?
Verified Explanation
Samarium-Cobalt (SmCo) magnets, developed in the early 1970s, are strong permanent magnets made of samarium and cobalt (SmCo5 or Sm2Co17). While NdFeB magnets are slightly stronger at room temperature, SmCo magnets have far superior thermal stability and corrosion resistance, operating effectively at temperatures up to 350°C in defense and aerospace applications.
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