Polyhalogen compounds

36 questions on Polyhalogen compounds from the Haloalkanes and Haloarenes chapter: 8 NEET level, 14 JEE Main, 14 JEE Advanced. Each one opens with its answer and solution.

• On exposure to air and light, chloroform slowly forms a highly poisonous gas, which is NEET level
• Chloroform, an aliphatic primary amine and alcoholic KOH on warming give a foul-smelling compound. This compound is an NEET level
• The freon with the formula CCl2F2 is known as NEET level
• DDT is prepared by heating chlorobenzene with NEET level
• Which of the following does NOT give the iodoform test with I2 and aqueous NaOH? JEE Main level
• In the Reimer-Tiemann reaction, phenol is heated with chloroform and aqueous NaOH to give salicylaldehyde. The electrophile that attacks the phenoxide ring is JEE Main level
• Chloretone, a hypnotic, is obtained when acetone reacts with chloroform in the presence of solid KOH. Its structure is JEE Main level
• Chlorofluorocarbons cause depletion of stratospheric ozone mainly because ultraviolet radiation breaks CF2Cl2 to release JEE Main level
• The Freon with the number 113 has the molecular formula JEE Main level
• Tetrachloroethene, Cl2C=CCl2, is mainly used as JEE Main level
• A methyl ketone CH3COR is treated with excess I2 and NaOH. The number of moles of I2 consumed per mole of pentan-2-one, CH3COCH2CH2CH3, to form iodoform is JEE Main level
• Acetone (5.8 g) is treated with excess I2 and aqueous NaOH and gives iodoform with 80 percent yield. Use CH3COCH3 + 3I2 + 4NaOH -> CHI3 + CH3COONa + 3NaI + 3H2O... JEE Advanced level
• Which of the following give a yellow precipitate of iodoform on warming with I2 and aqueous NaOH? JEE Advanced level
• Which statements about chloroform and carbon tetrachloride are correct? JEE Advanced level
• Which statements about DDT and BHC are correct? JEE Advanced level
• Which statements about chlorofluorocarbons are correct? JEE Advanced level
• Assume that 1 mol of CHCl3 and 1 mol of CCl4 are both hydrolysed completely by excess aqueous KOH (chloroform to HCOOK, carbon tetrachloride to K2CO3, with all ... JEE Advanced level
• An organic compound X, C4H8O, gives a yellow precipitate with I2/NaOH and the sodium salt obtained in solution contains three carbon atoms. X is JEE Advanced level
• Chloroform is slowly oxidised by air in the presence of light to form a highly poisonous gas. The gas is NEET level
• About 1 percent of ethanol is added to commercial chloroform in order to NEET level
• The refrigerant Freon-12 (CFC-12) has the formula NEET level
• DDT is prepared by heating chlorobenzene with NEET level
• Which of the following does NOT give a yellow precipitate when warmed with I2 and aqueous NaOH? JEE Main level
• 0.25 mol of hexane-2,5-dione, CH3-CO-CH2-CH2-CO-CH3, is treated with excess alkaline iodine until both CH3CO groups have undergone the iodoform reaction (each C... JEE Advanced level
• Chloroform on warming with concentrated nitric acid gives a compound used as an insecticide and as a tear gas. The compound is JEE Main level
• Chloroform condenses with propanone in the presence of solid KOH to give a hypnotic drug (chloretone). Its structure is JEE Main level
• In the Reimer-Tiemann reaction of phenol with CHCl3 and aqueous NaOH, the electrophile that attacks the phenoxide ring is JEE Main level
• The mass percentage of chlorine in DDT, C14H9Cl5 (atomic masses: C 12, H 1, Cl 35.5), is closest to JEE Main level
• Which of the following give a yellow precipitate of iodoform on warming with I2 and aqueous NaOH? JEE Main level
• Select the correct matches of Freon number with formula (rule of 90). JEE Main level
• Ethanamine is heated with CHCl3 and alcoholic KOH to give X. X is reduced with H2 over Ni to give Y. Y is JEE Advanced level
• Exactly three of the four chlorine atoms of CCl4 are replaced by fluorine (Swarts reaction) to give a chlorofluorocarbon. Using the rule of 90, its Freon number... JEE Advanced level
• p-Cresol (4-methylphenol) is treated with CHCl3 and aqueous NaOH and then acidified. The main product is JEE Advanced level
• Chlorobenzene (112.5 g) is heated with chloral, CCl3CHO (147.5 g), and concentrated H2SO4 to make DDT, C14H9Cl5 (molar mass 354.5 g mol^-1) with loss of water. ... JEE Advanced level
• Methane (8.0 g, atomic masses C 12, H 1, Cl 35.5) is completely chlorinated to CCl4 with excess chlorine under UV light. The mass of Cl2 consumed is JEE Advanced level
• Select the correct statements. JEE Advanced level