Distilled water is considered the purest form of water because:
A. It is free from dissolved salts and impurities
B. It is carbonated
C. It has a high pH
D. It contains beneficial minerals
Answer: Option A
Solution (By JKExamLibrary)
Distilled water is produced by boiling water and condensing the steam, leaving behind non-volatile impurities like salts, minerals, and most contaminants. It is almost pure H₂O. Deionized water also has salts removed. However, it may absorb CO₂ and become slightly acidic. It is used in laboratories and batteries.
Explanation:
When cement hydrates, it releases heat known as heat of hydration. This exothermic process can cause thermal cracking in massive concrete structures if not controlled. The main compounds C₃S and C₃A have high heat of hydration. For dams, low-heat cement with lower C₃A content is used. Heat of solution is for dissolving, combustion for burning, fusion for melting.
Explanation:
Bleaching powder is calcium oxychloride, CaOCl₂. It is produced by passing chlorine over dry slaked lime: Ca(OH)₂ + Cl₂ → CaOCl₂ + H₂O. It is a mixed salt of Ca²⁺, Cl⁻, and OCl⁻ ions. It is used for bleaching and disinfection.
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