Chemistry Discoveries — Set 2
Inventions · रसायन की खोजें · Questions 11–20 of 70
Who discovered Penicillin, the world's first true antibiotic, in 1928?
Correct Answer: C. Alexander Fleming
• **Alexander Fleming** = discovered Penicillin, the world's first true antibiotic, by observing mold destroying bacteria. • **1928** — the year Fleming made his accidental discovery, revolutionizing infectious disease treatment. • 💡 Wrong-option analysis: Louis Pasteur: known for pasteurization and germ theory; Selman Waksman: discovered streptomycin and coined 'antibiotic'; Robert Koch: identified specific disease-causing microorganisms.
The discovery of X-rays, which helped reveal chemical structures, was made by?
Correct Answer: C. Wilhelm Röntgen
• **Wilhelm Röntgen** = discovered X-rays, a high-energy radiation that helped reveal chemical structures. • **1895** — the year Röntgen discovered X-rays while experimenting with vacuum tubes, taking the first medical X-ray. • 💡 Wrong-option analysis: Henry Moseley: used X-ray spectroscopy to determine atomic number; William Bragg: developed Bragg's Law for X-ray diffraction; Max von Laue: demonstrated X-ray diffraction in crystals.
Who is known for developing the modern concept of acids and bases involving proton transfer?
Correct Answer: C. Johannes Brønsted
• **Johannes Brønsted** = developed the modern concept of acids and bases involving proton transfer. • **1923** — the year Brønsted (with Thomas Lowry) independently proposed this proton-transfer theory, expanding acid-base understanding. • 💡 Wrong-option analysis: S.P.L. Sørensen: introduced the pH scale; Svante Arrhenius: proposed an earlier acid-base theory limited to aqueous solutions; Gilbert Lewis: developed the Lewis acid-base theory based on electron pair donation/acceptance.
The discovery that the atomic number, not atomic weight, is the key to the periodic table was made by?
Correct Answer: D. Henry Moseley
• **Henry Moseley** = discovered that the atomic number, not atomic weight, is the key to the periodic table's arrangement. • **1913** — the year Moseley used X-ray spectroscopy to confirm the fundamental importance of atomic number. • 💡 Wrong-option analysis: Lothar Meyer: contributed to early periodic table development based on atomic weight; Ernest Rutherford: discovered the atomic nucleus; Glenn Seaborg: known for synthesizing transuranic elements and redesigning the periodic table.
Who discovered Hydrogen, referring to it as 'inflammable air'?
Correct Answer: B. Henry Cavendish
• **Henry Cavendish** = discovered Hydrogen, initially referring to it as 'inflammable air'. • **1766** — the year Cavendish first recognized hydrogen as a distinct substance and studied its properties. • 💡 Wrong-option analysis: Humphry Davy: isolated several elements using electrolysis; Daniel Rutherford: discovered nitrogen; Joseph Black: discovered carbon dioxide.
The 'pH scale' for measuring acidity was invented by which chemist?
Correct Answer: C. S.P.L. Sørensen
• **S.P.L. Sørensen** = He introduced the pH scale, which measures acidity or alkalinity of a solution. • **1909** — the year he introduced the pH scale at the Carlsberg Laboratory in Denmark. • 💡 Wrong-option analysis: Linus Pauling: Known for theories on chemical bonding and electronegativity; Svante Arrhenius: Proposed the Arrhenius definition of acids and bases; Alfred Nobel: Swedish chemist, engineer, inventor, and founder of the Nobel Prizes.
Which scientist discovered the 'Law of Definite Proportions' in chemical compounds?
Correct Answer: B. Joseph Proust
• **Joseph Proust** = He formulated the Law of Definite Proportions, stating a chemical compound always contains the same elements in the same proportions by mass. • **The Law of Definite Proportions** — a fundamental concept in chemistry, distinguishing compounds from mixtures. • 💡 Wrong-option analysis: John Dalton: Formulated the atomic theory and Law of Multiple Proportions; Amedeo Avogadro: Proposed Avogadro's law regarding gases; Claude Berthollet: Argued against fixed proportions, leading to the Law of Definite Proportions.
Who discovered the noble gas Helium on Earth after it was detected in the Sun?
Correct Answer: B. William Ramsay
• **William Ramsay** = He successfully isolated helium on Earth in 1895 from the mineral cleveite. • **1895** — the year William Ramsay isolated helium on Earth, confirming its terrestrial presence. • 💡 Wrong-option analysis: Norman Lockyer: Co-discovered helium spectroscopically in the Sun's spectrum; Lord Rayleigh: Discovered argon and confirmed the existence of noble gases with Ramsay; Pierre Janssen: Co-discovered helium spectroscopically in the Sun's spectrum.
The discovery of 'Vaccination' as a chemical/biological defense was pioneered by?
Correct Answer: D. Edward Jenner
• **Edward Jenner** = He pioneered vaccination against smallpox by using cowpox in 1796. • **1796** — the year Edward Jenner conducted his pivotal experiment using cowpox to immunize against smallpox. • 💡 Wrong-option analysis: Jonas Salk: Developed the first successful inactivated polio vaccine; Albert Sabin: Developed the first oral live-attenuated polio vaccine; Louis Pasteur: Known for pasteurization and developing vaccines for rabies and anthrax, but after Jenner.
Who discovered the process of Vulcanization, making rubber durable?
Correct Answer: D. Charles Goodyear
• **Charles Goodyear** = He discovered vulcanization, a chemical process that transforms natural rubber into a more durable material by heating it with sulfur. • **Vulcanization** — a process that revolutionized the rubber industry and enabled the widespread use of rubber products. • 💡 Wrong-option analysis: Wallace Carothers: Invented nylon and neoprene; John Dunlop: Invented the pneumatic tire for bicycles; Leo Baekeland: Invented Bakelite, the first synthetic plastic.