If the volume of a gas is doubled at constant temperature, its pressure will: MCQ with Answer and Explanation

Explanation:
The modern periodic law states that the physical and chemical properties of elements are periodic functions of their atomic numbers. This was proposed by Henry Moseley, correcting Mendeleev's periodic table which was based on atomic mass. Atomic number determines the electronic configuration and thus chemical properties.

Explanation:
H₂O₂ is a strong oxidizing agent that damages bacterial cell walls, membranes, and essential biomolecules through oxidation, killing microorganisms. It is used as a 3% solution for wound cleaning. The foaming action is due to catalase in tissues breaking it down, releasing O₂. It is not a reducing agent, acid, or dehydrating agent.

Explanation:
Ozonation is a powerful disinfection method that kills bacteria and viruses faster than chlorine. Unlike chlorine, ozone decomposes back into oxygen and does not leave a residual taste or form harmful chlorinated organic byproducts (like trihalomethanes), making it safer for drinking water.