The technique used to separate colors in a dye is: MCQ with Answer and Explanation

Explanation:
Sodium has the electronic configuration [Ne]3s1. After losing one electron to form Na+, it achieves a highly stable noble gas configuration ([Ne]). Removing a second electron from this stable core requires an exceptionally large amount of energy. Thus, sodium has the highest second ionization energy among these elements.

Explanation:
V₂O₅ catalyzes the oxidation of SO₂ to SO₃ in the Contact process for sulfuric acid: 2SO₂ + O₂ ⇌ 2SO₃. Fe is used for ammonia (Haber). Pt-Rh gauze for nitric acid (Ostwald). Sodium hydroxide is made by chlor-alkali electrolysis, no catalyst needed. V₂O₅ is preferred over Pt because it is cheaper and less susceptible to poisoning by arsenic impurities.

Explanation:
Rhizobium bacteria form root nodules in leguminous plants (peas, beans, clover) and fix atmospheric N₂ into ammonia, providing nitrogen to the plant, while the plant supplies carbohydrates. Azotobacter and Azospirillum are free-living nitrogen fixers. Pseudomonas is a general soil bacterium. Symbiotic association is mutualistic. Inoculating seeds with Rhizobium culture increases soil fertility.