Water can dissolve more substances than any other liquid because
- A.it is dipolar in nature
- B.it is a good conductor of heat
- C.it has high value of specific heat
- D.it is an oxide of hydrogen
Correct answer
Explanation
The correct answer is A, it is dipolar in nature. Water is called the universal solvent because its molecule is polar: the oxygen end carries a partial negative charge and the two hydrogen ends carry partial positive charges. The molecule is bent at an angle of about 104.5°, so these charges do not cancel out. When a salt such as sodium chloride is put in water, the negative oxygen ends surround the sodium ions and the positive hydrogen ends surround the chloride ions, pulling the crystal apart; this is called hydration. Water also forms hydrogen bonds with polar substances such as sugar and alcohol, which is why they dissolve easily, while non-polar oil does not. Option B is wrong because water is in fact a poor conductor of heat, and heat conduction has nothing to do with dissolving. Option C is wrong because high specific heat explains why water warms up slowly, not why it dissolves things. Option D is wrong because being an oxide of hydrogen does not by itself make a liquid a good solvent. Exam tip: polar water dissolves polar and ionic substances, because like dissolves like.
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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