Everyday Chemistry — Set 5

Correct Answer: A. Nitrogen

Nitrogen is an inert gas that prevents the fats in snacks from reacting with oxygen and turning rancid. It also creates a cushion inside the bag to protect the chips from physical breakage. This process is known as 'modified atmosphere packaging' in the industry.

Correct Answer: D. Sodium Carbonate

Sodium carbonate is an effective cleaning agent used to remove stubborn stains and grease. It also acts as a water softener by precipitating calcium and magnesium ions. It is an important industrial chemical for glass and paper manufacturing.

Correct Answer: D. Aluminium

Aluminium is the most common metal, although silicon is a more abundant element in the crust overall. It is found in many minerals but is commercially extracted only from bauxite ore. Its low density and high corrosion resistance make it invaluable for modern industry.

Correct Answer: A. Calcium Carbide

Calcium carbide reacts with moisture to produce acetylene gas, which mimics the natural ripening hormone ethylene. However, its use is restricted in many places due to potential contamination with arsenic and phosphorus. Natural ripening is always preferred for better taste and safety.

Correct Answer: B. Ammonium Chloride

Ammonium chloride acts as the electrolyte in the form of a moist paste in Leclanché-style dry cells. It allows the movement of ions between the carbon rod and the zinc container. These batteries are disposable and used for low-drain devices like clocks and remotes.

Correct Answer: A. Neon

Neon gas glows with a bright orange-red light when a high voltage discharge passes through it. Other noble gases and mercury vapor are mixed to create a wide variety of different colors. These 'neon signs' have been a staple of urban lighting since the early twentieth century.

Correct Answer: B. Calcium Carbonate

Calcium carbonate exists in various forms including limestone, chalk, and metamorphic marble. It is a common substance in nature, found in rocks and the shells of marine organisms. In the classroom, chalk is used for writing because it leaves a soft, white residue.

Correct Answer: A. Sodium Hydroxide

Sodium hydroxide is a strong base that is highly corrosive to organic tissues. It is used in drain cleaners because it can dissolve hair and grease through chemical reactions. It is also essential for manufacturing textiles, paper, and various soaps.

Correct Answer: C. Synthetic Rubber

Modern erasers are typically made from synthetic rubber or vinyl for better performance and durability. They work by abrading the surface of the paper to lift and trap the graphite particles. Some specialized erasers also contain pumice to help remove stubborn marks.

Correct Answer: B. Thymol

Thymol is an antiseptic compound commonly used in mouthwashes like Listerine. It has antibacterial properties that help reduce oral bacteria. Potassium permanganate is used for water purification, not mouthwash.