Assertion (A): Pure water is a bad conductor of electricity. Reason (R): Pure water does not contain any dissolved ions. MCQ with Answer and Explanation

Explanation:
Ionization energy generally increases across a period due to increasing nuclear charge and decreasing atomic size. Among Na, Mg, Al, and Si (Period 3), Si has the highest effective nuclear charge and smallest size, thus requiring the maximum energy to remove the outermost electron from its gaseous state.

Explanation:
Carbon-14 (half-life ~5730 years) is used to determine the age of archaeological and geological organic samples up to ~50,000 years. Cobalt-60 for cancer; Am-241 for smoke detectors.

Explanation:
Caustic soda is NaOH (sodium hydroxide). It is a strong base used in soap, paper, and textile industries. Washing soda is Na₂CO₃, baking soda NaHCO₃. Caustic potash is KOH.