Everyday Chemistry — Set 3
Chemistry · रोजमर्रा का रसायन · Questions 21–30 of 50
Which chemical is the primary ingredient in common laundry bleach?
Correct Answer: A. Sodium Hypochlorite
Sodium hypochlorite acts as an oxidizing agent that removes stains and lightens fabrics. It is also a very effective sanitizer used for cleaning surfaces in households and hospitals. It should never be mixed with ammonia-based cleaners due to toxic gas formation.
Which metal is used as a coating on galvanized iron to prevent rusting?
Correct Answer: C. Zinc
Zinc provides a protective layer that prevents air and moisture from reaching the underlying iron. Even if the coating is scratched, the zinc corrodes preferentially, protecting the iron. This process is widely used for roofing sheets and water pipes.
Which gas is responsible for the 'rotten egg' smell near sewage or volcanic vents?
Correct Answer: C. Hydrogen Sulfide
Hydrogen sulfide is a colorless gas that is highly toxic and flammable. It is produced by the bacterial breakdown of organic matter in the absence of oxygen. The human nose can detect this gas at extremely low concentrations.
Which organic compound is commonly known as 'Wood Alcohol'?
Correct Answer: B. Methanol
Methanol was historically produced by the destructive distillation of wood. It is highly toxic and can cause blindness or death if ingested in small amounts. Industrially, it is used as a solvent and a precursor to other chemicals.
Which of the following is used in the manufacture of matches?
Correct Answer: D. Red Phosphorus
Red phosphorus is used on the striking surface of safety matchboxes. It is much more stable and less toxic than white phosphorus, which was used in earlier designs. Friction converts a tiny amount of it into white phosphorus to ignite the match head.
Which chemical is used to give a green color to firework displays?
Correct Answer: D. Barium salts
Barium compounds produce a brilliant green color when they burn in a pyrotechnic mixture. This is a standard ingredient in professional firework displays for varied visual effects. Precise chemical ratios are needed to ensure the color is vibrant.
Which chemical is often used as a preservative in processed fruit juices and jams?
Correct Answer: D. Sodium Benzoate
Sodium benzoate inhibits the growth of bacteria, molds, and yeasts in acidic environments. It is safe for human consumption in very small, regulated quantities. It is also found naturally in some fruits like cranberries and plums.
Which material is primarily used to make the filament of an incandescent light bulb?
Correct Answer: C. Tungsten
Tungsten has the highest melting point of all metallic elements in pure form. This allows the filament to reach very high temperatures and glow brightly without melting. The bulb is filled with inert gas to prevent the metal from oxidizing.
Which substance is added to table salt to prevent a specific nutritional deficiency?
Correct Answer: D. Iodine
Potassium iodate or iodide is added to salt to ensure adequate intake of iodine. This practice has significantly reduced the global incidence of goiter and related thyroid disorders. It is one of the most successful public health interventions in history.
What is the common name for Sodium Bicarbonate used in kitchens?
Correct Answer: C. Baking Soda
Baking soda is a versatile chemical used as a leavening agent in cooking. It reacts with acidic ingredients to produce carbon dioxide gas for rising. It is also frequently used as a gentle abrasive cleaner in households.