Which allotrope of carbon is the hardest natural substance? MCQ with Answer and Explanation

Explanation:
Evaporation increases with an increase in surface area, temperature, and wind speed, and decreases with an increase in humidity. A larger surface area allows more liquid molecules to be exposed to the air, enabling them to escape into the vapor phase more quickly, thus increasing the rate of evaporation.

Explanation:
Soaps react with Ca²⁺ and Mg²⁺ ions in hard water to form insoluble scum (calcium/magnesium stearate), wasting soap and reducing cleaning efficiency. Detergents form soluble salts with these ions, so they lather well and clean effectively in hard water. Both statements are correct and R explains A.

Explanation:
Henry Moseley (1913) established the concept of atomic number as the number of protons through X-ray spectra of elements. He showed that atomic number, not atomic mass, is the fundamental property for arranging elements in the periodic table, resolving anomalies in Mendeleev's table. He did not discover a particle but a principle. Modern periodic law is based on atomic number.