Which one of the following statements regarding Bleaching powder and D.D.T. is correct ?
- A.Both are inorganic compounds
- B.Both are organic compounds
- C.Both contain chlorine
- D.Both contain calcium
Correct answer
Explanation
The correct answer is C, Both contain chlorine. Bleaching powder is calcium oxychloride, CaOCl₂, and DDT is dichlorodiphenyltrichloroethane; chlorine is the one element common to both.
Bleaching powder is made by passing chlorine gas over dry slaked lime. It is an inorganic compound that releases chlorine, so it is used to disinfect drinking water and to bleach cotton, linen and wood pulp. DDT, with the formula C₁₄H₉Cl₅, is an organic compound built on carbon chains and rings and holding five chlorine atoms. It was widely used as an insecticide against malaria-carrying mosquitoes, but because it persists in the environment and builds up along food chains, its use is now banned or tightly restricted.
A is wrong: DDT is organic, so both are not inorganic. B is wrong: bleaching powder is inorganic, so both are not organic. D is wrong: bleaching powder contains calcium, but DDT has only carbon, hydrogen and chlorine.
Exam tip: bleaching powder = CaOCl₂ (from chlorine and slaked lime); DDT = organochlorine insecticide that biomagnifies.
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
Show answer
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.
Show answer
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
Show answer
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.
Show answer
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.
Show answer
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.
Read the full explanation →