Which of the following is NOT a method of water purification?
A. Electrolysis
B. Filtration
C. Chlorination
D. Boiling
Answer: Option A
Solution (By JKSSB Mock Tests)
Electrolysis of water decomposes it into hydrogen and oxygen, not purification. Boiling kills microbes, filtration removes particulate matter, chlorination disinfects. Other methods: UV treatment, ozonation, reverse osmosis, distillation. Electrolysis is a chemical decomposition technique.
Explanation:
In a double displacement reaction, ions of two compounds exchange places to form two new compounds. Here, Ba²⁺ and Na⁺ exchange their anions (Cl⁻ and SO₄²⁻) to form BaSO₄ (a white precipitate) and NaCl. This is also a precipitation reaction due to the formation of insoluble barium sulfate.
Explanation:
Elements in the same vertical column (group) have the same number of electrons in their outermost shell (valence electrons). This gives them similar chemical properties. The number of shells increases as we go down a group, leading to trends in atomic radius and ionization energy.
Explanation:
Teflon (PTFE) has a very low coefficient of friction and surface energy because the fluorine atoms form a protective shield around the carbon backbone, making it difficult for other substances to adhere. This is not due to polarity (C-F bonds are polar but the molecule overall is non-polar due to symmetry). It is extremely inert, resisting most chemicals.
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