Which of the following metals is stored under kerosene? MCQ with Answer and Explanation

Explanation:
Number of half-lives = total time / half-life = 10/5 = 2. Fraction remaining = (1/2)ⁿ = (1/2)² = 1/4. Thus 25% remains. After 3 half-lives (15 years) it would be 1/8.

Explanation:
Camphor sublimes—it directly changes from solid to vapor on heating without passing through the liquid phase. Other sublimable solids include naphthalene, iodine, ammonium chloride, and dry ice (solid CO₂). Sodium chloride, sugar, and sand melt or decompose on strong heating. Sublimation is used to separate sublimable substances from non-sublimable impurities. The process requires careful heating.

Explanation:
The element with atomic number 118 is Oganesson (Og). It is a synthetic element and a member of the noble gas group (Group 18). Ununennium is the temporary name for element 119, Tennessine is 117, and Nihonium is 113.