The atomic number of an element is 11. Its electronic configuration is:
A. 2, 8, 7
B. 2, 8, 2
C. 2, 8, 1
D. 2, 8, 8
Answer: Option C
Solution (By JKExamLibrary)
Atomic number 11 is sodium (Na). The electron shells fill as 2 in K, 8 in L, and the remaining 1 in M. Thus configuration is 2,8,1. It belongs to Group 1 (alkali metals) and Period 3. The configuration determines its valency (1) and reactivity.
Explanation:
In the Contact process, the key catalytic step is oxidation of SO₂ to SO₃ using V₂O₅ (vanadium pentoxide) catalyst at 450°C: 2SO₂ + O₂ ⇌ 2SO₃. Sulfur burning is non-catalytic. The SO₃ is absorbed in 98% H₂SO₄ to form oleum (H₂S₂O₇), then diluted to get concentrated H₂SO₄. Direct dissolution of SO₃ in water is avoided due to mist formation.
Explanation:
Crystallization separates a pure solid from a solution by cooling or evaporating the solvent. Impurities remain in the mother liquor. Example: purifying copper sulfate. Distillation for liquids; filtration for insoluble solids.
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