Chemistry Discoveries — Set 3

Correct Answer: D. Ernest Rutherford

• **Ernest Rutherford** = He is credited with the discovery of the proton in 1917, identifying it as the hydrogen nucleus. • **1917** — the year Ernest Rutherford identified the proton during experiments involving alpha particles and nitrogen. • 💡 Wrong-option analysis: J.J. Thomson: Discovered the electron; Niels Bohr: Proposed the Bohr model of the atom; James Chadwick: Discovered the neutron.

Correct Answer: A. Humphry Davy

• **Humphry Davy** = He pioneered the use of electrolysis to isolate elements like sodium, potassium, calcium, and magnesium. • **Electrolysis** — a process he successfully applied to isolate several alkali and alkaline earth metals. • 💡 Wrong-option analysis: Alessandro Volta: Invented the electric battery (voltaic pile); Joseph Priestley: Discovered oxygen; Michael Faraday: Later formalized the laws of electrolysis and discovered electromagnetic induction; was Davy's assistant.

Correct Answer: D. John Newlands

• **John Newlands** = He formulated the Law of Octaves, observing a repetition of properties every eighth element when arranged by atomic mass. • **The Law of Octaves** — an early attempt to classify elements, recognizing periodicity in properties. • 💡 Wrong-option analysis: Johann Döbereiner: Proposed the Law of Triads; Dmitri Mendeleev: Developed the first widely accepted periodic table; Lothar Meyer: Also published a periodic table independently around the same time as Mendeleev, based on atomic volume.

Correct Answer: B. August Kekulé

• **August Kekulé** = He proposed the cyclic structure of benzene, famously claiming the idea came to him in a dream about an ouroboros (snake biting its tail). • **Benzene ring structure** — a foundational discovery in organic chemistry, explaining the stability of aromatic compounds. • 💡 Wrong-option analysis: Friedrich Wöhler: Synthesized urea, disproving vitalism; Jacobus van 't Hoff: Contributed to the development of chemical thermodynamics and stereochemistry; Linus Pauling: Known for theories on chemical bonding and electronegativity, also for 'Pauling scale'.

Correct Answer: C. Friedrich Wöhler

• **Friedrich Wöhler** = He synthesized urea from inorganic compounds in 1828, a landmark event that disproved the theory of vitalism. • **1828** — the year Friedrich Wöhler synthesized urea, marking the beginning of modern organic chemistry. • 💡 Wrong-option analysis: Justus von Liebig: Known for contributions to agricultural and organic chemistry, but not for the first synthesis of urea; Hermann Kolbe: Synthesized acetic acid from inorganic sources; Louis Pasteur: Known for pasteurization and disproving spontaneous generation of life.

Correct Answer: D. John Dalton

• **John Dalton** = He formulated the Law of Partial Pressures, stating that in a mixture of non-reacting gases, the total pressure is the sum of the partial pressures of individual gases. • **The Law of Partial Pressures** — a fundamental gas law crucial for understanding gas behavior in mixtures. • 💡 Wrong-option analysis: Jacques Charles: Formulated Charles's Law (volume and temperature of a gas); Joseph Gay-Lussac: Formulated Gay-Lussac's Law (pressure and temperature of a gas) and the Law of Combining Volumes; Robert Boyle: Formulated Boyle's Law (pressure and volume of a gas).

Correct Answer: B. Harold Urey

• **Harold Urey** = He discovered deuterium, a heavy isotope of hydrogen, in 1931, leading to the understanding and production of heavy water. • **1931** — the year Harold Urey discovered deuterium, a key component of heavy water. • 💡 Wrong-option analysis: Irving Langmuir: Contributed to gas-filled lamps and surface chemistry; coined the term 'octet'; Linus Pauling: Known for theories on chemical bonding and electronegativity; Gilbert Lewis: Known for the electron-pair bond theory, Lewis structures, and the concept of an octet.

Correct Answer: A. Gaston Planté

• **Gaston Planté** = He invented the first lead-acid rechargeable battery in 1859, a design still used in vehicles today. • **1859** — the year Gaston Planté invented the lead-acid battery, marking the beginning of practical rechargeable energy storage. • 💡 Wrong-option analysis: Thomas Edison: Patented the nickel-iron alkaline storage battery; Alessandro Volta: Invented the voltaic pile, the first true electric battery (non-rechargeable); John Daniell: Invented the Daniell cell, an improved primary (non-rechargeable) battery.

Correct Answer: D. Gilbert Lewis

• **Gilbert Lewis** = He developed the electron-pair bond theory and formulated the Octet Rule, explaining chemical bonding and stability. • **The Octet Rule** — a fundamental principle in chemistry explaining how atoms achieve stability through electron configurations. • 💡 Wrong-option analysis: Niels Bohr: Proposed the Bohr model of the atom with electrons orbiting in fixed shells; Richard Abegg: Noted that elements tend to combine such that their valencies sum to eight, an early precursor to the octet rule; Linus Pauling: Developed concepts of electronegativity and resonance; further elaborated on chemical bonding.

Correct Answer: A. Leo Baekeland

• **Leo Baekeland** = He invented Bakelite in 1907, the first fully synthetic, thermosetting plastic, revolutionizing materials science. • **1907** — the year Leo Baekeland invented Bakelite, marking a pivotal moment in the history of plastics. • 💡 Wrong-option analysis: Alexander Parkes: Created Parkesine, one of the earliest man-made plastics; John Hyatt: Developed celluloid, an early plastic and substitute for ivory; Wallace Carothers: Invented nylon and neoprene, significant synthetic polymers.