Packets of potato chips are usually flushed with which one of the following gases to prevent rancidity?
- A.Carbon dioxide
- B.Hydrogen
- C.Nitrogen
- D.Oxygen
Correct answer
Explanation
The correct answer is C, Nitrogen. Nitrogen is an unreactive gas, so it drives the oxygen out of the packet and stops the oil in the chips from getting oxidised. Rancidity is the oxidation of fats and oils in food, which spoils their smell and taste. Chips are fried in oil, so they turn rancid quickly once they meet air. Filling the pack with nitrogen keeps oxygen out and also acts as a cushion that stops the chips from breaking in transport. Other ways to slow rancidity are adding antioxidants, storing food in airtight containers and keeping it in a refrigerator. Option A is wrong because carbon dioxide is used for fizzy drinks and some other foods, but the standard gas for chips is nitrogen, which is cheap and very unreactive. Option B is wrong because hydrogen is highly inflammable and unsafe inside food packs. Option D is wrong because oxygen is the very gas that causes rancidity in the first place. Exam tip: rancidity is oxidation of fats; nitrogen flushing and antioxidants prevent it.
Practice Questions
View allThe fact that the planets move around the Sun, not in circles but in ellipses, was first demonstrated by
- A.Galileo
- B.Martin Luther
- C.Johannes Kepler
- D.Copernicus
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In 1609 Kepler showed that the planets move around the Sun in elliptical orbits, with the Sun at one focus of the ellipse.
Read the full explanation →Which one of the following statements is correct?
- A.Urea is produced in liver.
- B.Urea is produced in blood.
- C.Urea is produced from digestion of starch.
- D.Urea is produced in lung and kidney.
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Liver cells turn the toxic ammonia released from the breakdown of amino acids into urea through the ornithine cycle, also called the urea cycle.
Read the full explanation →Which one of the following is the correct sequence of passage of light in a compound microscope?
- A.Condenser-Objective lens-Eyepiece-Body tube
- B.Objective lens-Condenser-Body tube-Eyepiece
- C.Condenser-Objective lens-Body tube-Eyepiece
- D.Eyepiece-Objective lens-Body tube-Mirror
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Light passes through the condenser to the specimen, is picked up by the objective lens, travels up the body tube and reaches the eye through the eyepiece.
Read the full explanation →Which one of the following statements regarding haemoglobin is correct?
- A.Haemoglobin present in RBC can carry only oxygen but not carbon dioxide.
- B.Haemoglobin of RBC can carry both oxygen and carbon dioxide.
- C.Haemoglobin of RBC can carry only carbon dioxide.
- D.Haemoglobin is only used for blood clotting and not for carrying gases.
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It binds oxygen at its iron-containing haem groups and carries some carbon dioxide on its protein chains. Each haemoglobin molecule has four polypeptide chains and four haem groups, and each haem iron can hold one oxygen molecule, forming oxyhaemoglobin in the lungs.
Read the full explanation →Which one of the following statements regarding histone proteins is correct?
- A.Histones are proteins that are present in mitochondrial membrane.
- B.Histones are proteins that are present in nucleus in association with DNA.
- C.Histones are proteins associated with lipids in the cytosol.
- D.Histones are proteins associated with carbohydrates in the cytosol.
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They are the proteins around which DNA winds to form chromatin in the nucleus of eukaryotic cells. Histones are small basic proteins, rich in the positively charged amino acids lysine and arginine, which attract the negatively charged phosphate groups of DNA.
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