Which scientist arranged elements in increasing order of atomic weights and grouped them by similar properties?
A. Antoine Lavoisier
B. Dmitri Mendeleev
C. Henry Moseley
D. John Newlands
Answer: Option B
Solution (By JKExamLibrary)
Dmitri Mendeleev formulated the Periodic Law based on atomic masses and left gaps for undiscovered elements. Moseley later modified it to atomic number. Newlands gave Law of Octaves. Lavoisier classified elements into metals and non-metals.
Explanation:
Chromium (minimum 10.5%) forms a thin, adherent, transparent oxide layer (Cr₂O₃) on the surface, preventing further oxidation. Nickel adds ductility and enhances corrosion resistance. Iron is the base; carbon is for hardness but not corrosion resistance.
Explanation:
Incomplete combustion due to insufficient oxygen produces carbon monoxide (CO) and/or soot (C). Complete combustion gives CO₂ and H₂O. CO is poisonous, binds to hemoglobin.
Explanation:
Boyle's law states that at constant temperature, the volume of a given mass of gas is inversely proportional to pressure: PV = constant. So P ∝ 1/V. Charles' law relates V and T at constant P. Gay-Lussac's law relates P and T at constant V. Boyle's law is used in syringes and scuba diving. Graph of P vs V is a hyperbola; P vs 1/V is a straight line.
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