Antoine Lavoisier, an 18th-century French chemist, is widely considered the father of modern chemistry. He transformed chemistry from a qualitative to a quantitative science, established the law of conservation of mass, debunked the phlogiston theory, and helped reform chemical nomenclature.
Explanation:
A solution turning red litmus blue is basic, so pH > 7. Among options, pH 9 is basic. pH 2 and 5 are acidic (blue litmus turns red). pH 7 is neutral. Litmus is a natural indicator extracted from lichens. Red litmus in base remains blue, blue litmus in acid turns red. Practical: Phenolphthalein gives pink in basic solution (pH > 8.3).
Explanation:
Graphite's carbon atoms are arranged in layers held together by weak van der Waals forces. Layers can slide over each other, reducing friction. It is stable at high temperatures, so used where oil would decompose.
Explanation:
Reverse osmosis (RO) uses pressure to force water through a membrane that blocks dissolved salts and impurities. Distillation uses boiling/condensation. Chlorination and ozonation are disinfection methods, not for desalination.
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