50 questions on this topic of Organic Compounds Containing Halogens (NEET 2027 syllabus). Here are 12; tap one to see its answer and explanation.
Free with a Google sign-in; NEET Daily needs no sign-in at all.
Answer: (C) CF₂Cl₂, Dichlorodifluoromethane
Freon-12 is manufactured from tetrachloromethane by Swarts reaction and has the chemical formula CF₂Cl₂. Its IUPAC name is dichlorodifluoromethane.
Answer: (A) 100,000
The chlorine radical acts as a catalyst in ozone breakdown. According to environmental chemistry and NCERT data, a single chlorine atom can break down around 100,000 (10⁵) ozone molecules before being scavenged or removed from the stratosphere.
Answer: (B) 12 sp² and 2 sp³
The molecule p,p'-DDT contains two benzene rings, contributing a total of 12 aromatic sp²-hybridized carbon atoms (6 in each ring). The aliphatic bridge consists of -CH-CCl₃, which contains 2 sp³-hybridized carbon atoms. Total = 12 sp² and 2 sp³.
Answer: (B) Chloroform is highly inflammable and burns spontaneously in the absence of oxygen.
Chloroform is not highly inflammable; in fact, it is non-flammable under standard conditions. The other three statements are direct facts from NCERT concerning its physiological effects and replacement as a general anaesthetic.
Answer: (C) 5
DDT has the structure 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane. It contains 3 chlorine atoms in the trichloromethyl group and 1 chlorine atom on each of the two phenyl rings, giving a total of 5 chlorine atoms per molecule.
Answer: (C) 13.82%
Molar mass of CFCl₃ = 12 + 19 + (3 × 35.5) = 12 + 19 + 106.5 = 137.5 g/mol. Mass of fluorine = 19 g. Mass percentage of F = (19 / 137.5) × 100 = 13.818% ≈ 13.82%.
Answer: (C) Yellow crystalline solid with an unpleasant objectionable odour
NCERT describes iodoform (CHI₃) as a distinct yellow crystalline solid. It possesses a persistent and characteristically unpleasant, medicinal odour.
Answer: (C) Commercial preparation of chlorofluorocarbons relies on direct fluorination using F₂ gas at high temperatures.
Freon-12 is manufactured from carbon tetrachloride (tetrachloromethane) by the Swarts reaction using antimony trifluoride (SbF₃) in the presence of SbCl₅ as a catalyst, not by direct fluorination with elemental F₂ gas. All other statements are accurate factual points from the NCERT textbook.
Answer: (A) Swarts reaction using SbF₃ in the presence of SbCl₅
Freon-12 is manufactured industrially from CCl₄ through halogen exchange using antimony trifluoride (SbF₃) catalyzed by antimony pentachloride (SbCl₅), which is known as the Swarts reaction.
Answer: (A) A-IV, B-III, C-II, D-I
Chloroform is a precursor for the production of Freon-22 (R-22). Iodoform was formerly used as an antiseptic. Freon-12 (CF₂Cl₂) is used as a propellant and refrigerant. DDT bioaccumulates in birds, interfering with calcium metabolism and causing eggshell thinning. Therefore, the correct matching is A-IV, B-III, C-II, D-I.
Answer: (A) 1,1,1-Trichloro-2,2-bis(4-chlorophenyl)ethane
The chemical structure of p,p'-DDT is 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane. It consists of an ethane backbone with three chlorine atoms on C-1 and two 4-chlorophenyl rings attached to C-2.
Answer: (C) Statement I is incorrect but Statement II is correct
Statement I is incorrect because DDT has extremely low solubility in water. Statement II is correct because it has high lipid solubility, causing it to resist metabolism and accumulate in fatty tissues (biomagnification).