Which of the following is NOT a property of metals?
A. Ductility
B. Malleability
C. Good conductivity
D. Brittleness
Answer: Option D
Solution (By JKExamLibrary)
Metals are malleable (can be beaten into sheets), ductile (drawn into wires), and good conductors. Brittleness is a characteristic of non-metals and some metalloids; metals can deform without breaking. For example, gold is highly malleable.
Explanation:
Water (H₂O) is a compound – a pure substance composed of two or more elements chemically combined in a fixed ratio. Oxygen is an element. Air is a mixture of gases. Steel is an alloy (mixture). Compounds can be broken down by chemical methods.
Explanation:
Beta particles are high-energy, high-speed electrons (β⁻) or positrons (β⁺) emitted from a radioactive nucleus during beta decay. In β⁻ decay, a neutron converts to a proton, emitting an electron and an antineutrino. Beta particles have moderate penetrating power; they can be stopped by a few millimeters of aluminum. They cause less ionization than alpha.
Explanation:
Soap is made by saponification: fat/oil (triglyceride) + NaOH → glycerol + sodium salt of fatty acid (soap). This is an alkaline hydrolysis. HCl would break down differently. NaCl is used to precipitate soap (salting out). Ethanol is solvent.
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