Which sodium compound is the most popular additive to various items such as sauces, salad dressings and beverages for Its preservative action?
- A.Sodium bicarbonate
- B.Sodium fluoride
- C.Sodium hypochlorite
- D.Sodium benzoate
Correct answer
Explanation
The correct answer is D, Sodium benzoate. Sodium benzoate is the sodium salt of benzoic acid and is the preservative most often added to sauces, salad dressings, jams, pickles and soft drinks. It works best in acidic foods, where part of it turns into benzoic acid, and that stops the growth of moulds, yeasts and many bacteria. It dissolves easily in water, costs little and does not change the taste of the food, which is why it is so widely used; on labels it appears as INS 211 or E211. A is wrong because sodium bicarbonate is baking soda, used as a raising agent in cooking and as an antacid. B is wrong because sodium fluoride is added to toothpaste and drinking water to protect teeth, not to preserve food. C is wrong because sodium hypochlorite is the bleaching and disinfecting agent used in household bleach. Exam tip: common food preservatives - sodium benzoate, sodium metabisulphite and potassium metabisulphite; salt and sugar are the oldest of all.
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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