Mendeleev's periodic table had anomalies because he arranged elements by:
A. Atomic number
B. Electronegativity
C. Density
D. Atomic mass
Answer: Option D
Solution (By JKExamLibrary)
Mendeleev used atomic mass as basis. Anomalies like Ar (mass 40) placed before K (mass 39) occurred. These were resolved when Moseley proposed atomic number as the basis.
Explanation:
Boiling water changes state from liquid to gas, but the chemical composition (H₂O) remains unchanged – physical change. Others form new substances.
Explanation:
Charles' law: V ∝ T at constant pressure and for a fixed mass (n constant). If pressure or amount changes, the relationship does not hold. The temperature must be in Kelvin.
Explanation:
Bayer's process uses hot NaOH to dissolve alumina from bauxite, leaving behind insoluble impurities (red mud). Alumina is then precipitated. Hall-Héroult is electrolytic reduction of alumina to aluminium.
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