Chemistry Discoveries — Set 5
Inventions · रसायन की खोजें · Questions 41–50 of 70
Who discovered the element 'Magnesium' as a distinct substance?
Correct Answer: B. Joseph Black
• **Joseph Black** = recognized magnesium as an element in 1755 when he differentiated it from calcium. • **1755** — the year Joseph Black differentiated magnesium from calcium, establishing it as a distinct substance. • 💡 Wrong-option analysis: Humphry Davy: first isolated magnesium in metallic form in 1808; Carl Scheele: discovered many elements but not magnesium; Antoine Lavoisier: formulated the Law of Conservation of Mass.
Which chemist discovered 'Uranium' in 1789?
Correct Answer: B. Martin Heinrich Klaproth
• **Martin Heinrich Klaproth** = discovered uranium in 1789 while analyzing the mineral pitchblende. • **1789** — the year Klaproth discovered uranium, naming it after the recently discovered planet Uranus. • 💡 Wrong-option analysis: Henri Becquerel: discovered radioactivity, often associated with uranium; Eugene Peligot: first isolated pure uranium metal in 1841; Marie Curie: pioneered research on radioactivity and discovered polonium and radium.
Who discovered 'Aspirin' (Acetylsalicylic acid) in its stable form?
Correct Answer: A. Felix Hoffmann
• **Felix Hoffmann** = synthesized a stable form of acetylsalicylic acid, known as aspirin, in 1897. • **1897** — the year Hoffmann synthesized stable aspirin, making it a widely used medicine for pain and fever. • 💡 Wrong-option analysis: Arthur Eichengrün: was Hoffmann's supervisor and claimed to have directed the synthesis, but Hoffmann is generally credited; Charles Gerhardt: first synthesized acetylsalicylic acid in 1853 but did not achieve a stable form; Edward Stone: documented the use of willow bark for fever in 1763, containing salicylic acid.
The discovery of 'Nitrogen' is generally attributed to which scientist?
Correct Answer: B. Daniel Rutherford
• **Daniel Rutherford** = isolated nitrogen in 1772 and called it 'noxious air' or 'phlogisticated air'. • **1772** — the year Rutherford isolated nitrogen, demonstrating it did not support life or combustion. • 💡 Wrong-option analysis: Joseph Priestley: discovered oxygen and several other gases; Carl Scheele: independently isolated nitrogen around the same time but Rutherford is generally credited; Henry Cavendish: discovered hydrogen and determined the composition of water.
Which chemist discovered 'Iodine' during the Napoleonic Wars?
Correct Answer: C. Bernard Courtois
• **Bernard Courtois** = discovered iodine in 1811 while extracting sodium and potassium salts from seaweed ash. • **1811** — the year Courtois discovered iodine by observing violet vapors when sulfuric acid was added to seaweed residue. • 💡 Wrong-option analysis: Humphry Davy: confirmed iodine as an element in 1813; Andre-Marie Ampere: known for his work in electromagnetism and also suggested a name for the new element; Joseph Gay-Lussac: investigated iodine and proposed its elemental nature.
Who is credited with the discovery of 'Lithium'?
Correct Answer: B. Johan August Arfwedson
• **Johan August Arfwedson** = Discovered lithium in 1817 while analyzing the mineral petalite. • **1817** — the year of discovery; lithium is the lightest metal and the least dense solid element at room temperature. • 💡 Wrong-option analysis: Humphry Davy: discovered sodium and potassium; Carl Scheele: discovered oxygen and many organic acids; Jöns Jacob Berzelius: developed modern chemical notation and discovered silicon.
The discovery of 'Titanium' was made by which amateur chemist and clergyman?
Correct Answer: B. William Gregor
• **William Gregor** = Discovered titanium in 1791 while analyzing black sand from a stream in Cornwall. • **1791** — the year of discovery; titanium is famous for its high strength and resistance to corrosion. • 💡 Wrong-option analysis: John Dalton: developed the atomic theory; Joseph Black: discovered carbon dioxide; Martin Klaproth: independently rediscovered and named titanium.
Who discovered the 'Law of Combining Volumes' for gases?
Correct Answer: D. Joseph Louis Gay-Lussac
• **Joseph Louis Gay-Lussac** = He stated that when gases react, they do so in volumes that bear a simple whole-number ratio to each other. • **Amedeo Avogadro** — his hypothesis was helped by this discovery; it provided crucial evidence for the atomic and molecular nature of matter. • 💡 Wrong-option analysis: Robert Boyle: formulated Boyle's Law; John Dalton: proposed the atomic theory; Amedeo Avogadro: formulated Avogadro's Law.
Which scientist discovered 'Neon', 'Argon', and 'Xenon'?
Correct Answer: A. William Ramsay
• **William Ramsay** = He worked with Lord Rayleigh to discover the whole family of noble gases in the atmosphere. • **1894** — the year Argon was found by them; these gases were revolutionary as they were found to be completely chemically inert. • 💡 Wrong-option analysis: Joseph Priestley: independently discovered oxygen; Carl Scheele: independently discovered oxygen; Lord Rayleigh: co-discovered argon with Ramsay.
Who is the first person to have discovered 'Vanadium', although it was initially confused with another element?
Correct Answer: C. Andrés Manuel del Río
• **Andrés Manuel del Río** = He discovered 'erythronium' in 1801, which was later confirmed to be vanadium. • **1801** — the year Del Río discovered erythronium; **1830** — Sefström rediscovered it and named it Vanadium. • 💡 Wrong-option analysis: Nils Gabriel Sefström: rediscovered vanadium in 1830; Jöns Jacob Berzelius: developed modern chemical notation; Friedrich Wöhler: synthesized urea.