Chemistry Discoveries — Set 4
Inventions · रसायन की खोजें · Questions 31–40 of 70
Which scientist discovered the 'Law of Conservation of Mass'?
Correct Answer: B. Antoine Lavoisier
• **Antoine Lavoisier** = demonstrated that mass is neither created nor destroyed during a chemical reaction. • **1770s** — established this fundamental principle through quantitative experiments. • 💡 Wrong-option analysis: Robert Boyle: known for Boyle's Law of gases; Joseph Proust: known for the Law of Definite Proportions; John Dalton: known for the Atomic Theory and Law of Multiple Proportions.
Who is credited with the discovery of Carbon Dioxide, which he called 'fixed air'?
Correct Answer: A. Joseph Black
• **Joseph Black** = discovered carbon dioxide in the 1750s by heating magnesium carbonate. • **1750s** — demonstrated that this 'air' was different from common air because it extinguished flames and suffocated animals. • 💡 Wrong-option analysis: Daniel Rutherford: discovered nitrogen; Henry Cavendish: discovered hydrogen and water's composition; Carl Scheele: discovered oxygen, chlorine, and several other elements.
Which chemist discovered 'Dynamite', a safer way to use nitroglycerin?
Correct Answer: D. Alfred Nobel
• **Alfred Nobel** = mixed nitroglycerin with an absorbent substance called kieselguhr to make dynamite stable and portable. • **1867** — the year dynamite was patented, revolutionizing construction and mining. • 💡 Wrong-option analysis: Ascanio Sobrero: discovered nitroglycerin, which Nobel later stabilized; Herman Frasch: invented the Frasch process for sulfur extraction; Christian Schönbein: discovered ozone and gun cotton.
Who discovered the process of 'Pasteurization' to kill harmful microbes in liquids?
Correct Answer: C. Louis Pasteur
• **Louis Pasteur** = discovered that heating milk and wine could kill bacteria without altering the taste significantly. • **1864** — when the first pasteurization test was performed, greatly reducing foodborne illnesses. • 💡 Wrong-option analysis: Robert Koch: identified the specific causative agents of diseases like anthrax and tuberculosis; Antonie van Leeuwenhoek: known as the 'Father of Microbiology' for his improvements of the microscope; Joseph Lister: pioneered antiseptic surgery.
The discovery of 'Nylon', the first synthetic fiber, was led by?
Correct Answer: A. Wallace Carothers
• **Wallace Carothers** = and his team at DuPont synthesized Nylon 66, the first commercially successful synthetic thermoplastic polymer. • **1935** — the year Nylon 66 was synthesized, making its first major use for toothbrush bristles. • 💡 Wrong-option analysis: Stephanie Kwolek: invented Kevlar; Roy Plunkett: discovered Teflon; Charles Goodyear: invented vulcanized rubber.
Which scientist discovered 'Chlorine' gas, though he did not recognize it as an element?
Correct Answer: B. Carl Wilhelm Scheele
• **Carl Wilhelm Scheele** = isolated chlorine in 1774 by reacting manganese dioxide with hydrochloric acid. • **1774** — the year Scheele isolated chlorine, although Humphry Davy later recognized it as an element. • 💡 Wrong-option analysis: Humphry Davy: identified chlorine as an element in 1810; Antoine Lavoisier: formulated the Law of Conservation of Mass; Joseph Priestley: discovered oxygen.
Who discovered 'Polythene' (Polyethylene), now the most common plastic in the world?
Correct Answer: D. Eric Fawcett and Reginald Gibson
• **Eric Fawcett and Reginald Gibson** = accidentally discovered polyethylene in 1933 at ICI laboratories. • **1933** — the year polyethylene was accidentally discovered during high-pressure experiments with ethylene. • 💡 Wrong-option analysis: Wallace Carothers: led the discovery of Nylon; Leo Baekeland: invented Bakelite, the first synthetic plastic; Roy Plunkett: discovered Teflon.
Which chemist discovered 'Teflon' (PTFE) by accident?
Correct Answer: A. Roy Plunkett
• **Roy Plunkett** = discovered Teflon by accident while researching refrigerants at DuPont. • **1938** — the year Plunkett discovered Teflon (PTFE), famous for its non-stick and chemical-resistant properties. • 💡 Wrong-option analysis: Charles Goodyear: invented vulcanized rubber; Wallace Carothers: led the discovery of Nylon; Eric Fawcett: co-discovered polyethylene.
Who is known for the discovery of 'Bromine'?
Correct Answer: A. Antoine Jérôme Balard
• **Antoine Jérôme Balard** = is credited with the discovery of bromine, which he isolated from seawater. • **1826** — Balard published his detailed findings, establishing his priority for discovering this element. • 💡 Wrong-option analysis: Carl Jacob Löwig: independently isolated bromine in 1825 but published his results after Balard; All of the mentioned: is not the primary answer as Balard published first and is typically given primary credit; Neither A nor B: is incorrect as both individuals did discover bromine.
The discovery of 'Manganese' in its metallic form was achieved by?
Correct Answer: B. Johan Gottlieb Gahn
• **Johan Gottlieb Gahn** = reduced manganese dioxide with carbon to isolate the metal in 1774. • **1774** — the year Gahn successfully isolated metallic manganese, an essential element for stainless steel production. • 💡 Wrong-option analysis: Martin Klaproth: discovered uranium and zirconium; Jöns Jacob Berzelius: developed modern chemical notation and discovered several elements; Carl Scheele: predicted manganese's existence and isolated many other elements but not manganese metal.