A radioactive sample decays to 1/4 of its original amount in 40 days. Its half-life is: MCQ with Answer and Explanation

Explanation:
The object to be plated is connected to the negative terminal (cathode). Metal ions from the electrolyte are reduced and deposited on the cathode. The anode is usually the plating metal, which dissolves to replenish the electrolyte. For example, in silver plating, the article is the cathode and silver bar is the anode.

Explanation:
Ammonia reacts with CO₂ to form urea, and with HNO₃ to form ammonium nitrate, both key nitrogenous fertilizers. Glass uses Na₂CO₃; cement uses CaCO₃/clay; soap uses NaOH.

Explanation:
Contact process: Sulfur or pyrite (FeS₂) is burned in air to form SO₂, then SO₂ is oxidized with O₂ over V₂O₅ catalyst to SO₃, which is absorbed in concentrated H₂SO₄ to produce oleum, then diluted to get H₂SO₄. Raw materials: sulfur (or pyrite), air, and water (for dilution). Not NaCl or NH₃.