January 2021

An unknown compound (A) was soluble in ether but only slightly soluble in water. It burned with a clear blue flame and combustion analysis showed it to have the molecular formula of C5H12O. It gave a positive test with the Jones reagent producing a new compound (B) with a formula of C5H10O. Compound B gave […]

Your friend of Question 160 still needs your help. A week later a low-melting solid, compound A, was isolated, which combustion analysis showed had composition C9H10O. The substance gave a precipitate when treated with 2,4-dinitrophenylhydrazine solution. Furthermore, when reacted with iodoform reagent, a yellow precipitate of CHI3 was observed. Acidification of the alkaline solution from the

A colorless liquid, bp 199–201°C, burns with a yellow, sooty flame. The sodium fusion test proved negative for the presence of halogens, nitrogen, and sulfur. The compound was not soluble in water, 5% aqueous sodium hydroxide, or 5% hydrochloric acid. However, it dissolved in sulfuric acid with evolution of heat. It did not give a

A high-boiling liquid, bp 202–204°C burns with a yellow, sooty flame. Sodium fusion indicates that halogens, nitrogen, and sulfur are not present. The compound is not soluble in water, dilute sodium bicarbonate solution, or dilute hydrochloric acid. However, it proved to be soluble in 5% aqueous sodium hydroxide solution. The compound gives a purple color

A hydrocarbon, compound A (C6H10), burned with a yellow, almost nonsmoky flame. On catalytic hydrogenation over platinum catalyst, it absorbed 1 mol of hydrogen to form compound B. It also decolorized a Br2–CH2Cl2 solution to yield a dibromo derivative, compound C. Ozonolysis of the hydrocarbon gave only one compound, D. Compound D gave a positive

An unknown organic liquid, compound A, was found to burn with a yellow, sooty flame and give a positive Lucas test (5 min). Upon treatment with sodium dichromate–sulfuric acid solution it produced compound B, which also burned with a yellow, sooty flame. Compound B gave a positive 2,4-dinitrophenylhydrazine test, but a negative result when treated

An unknown organic carboxylic acid, mp 139–141°C, burned with a yellow, sooty flame. The sodium fusion test showed that nitrogen was present. It did not react with p-toluenesulfonyl chloride, but did give a positive test when treated with 5% aqueous ferrous ammonium sulfate solution, acidified with 3 M H2SO4, and then followed by methanolic KOH

An unknown compound burned with a yellow, nonsmoky flame and was found to be insoluble in 5% sodium hydroxide solution but soluble in concentrated sulfuric acid. Measurement of its boiling point gave a range of 130–131°C. Combustion analysis gave a molecular formula of C5H8O. It was found to give a semicarbazone with a melting point

1.Conjugation of the functional group in alkyl isocyanates has little impact on the antisymmetric stretching vibration located near 2770 cm–1 Explain. 2.In the infrared spectrum of 2-aminoanthraquinone (I) two carbonyl stretching frequencies are observed at 1673.5 and 1625 cm–1 : (a) Assign carbonyl bands in the infrared spectrum to the carbonyl groups in structure I

In the figure below, the mass of the terminal hydrogen atoms on the acetylene is hypothetically varied from zero to infinity. The response of the symmetric stretching (3374 cm–1 ) and triple-bond stretching (1974 cm–1 ) modes to the change in mass is shown. (a) Calculate the expected deuterium isotope shift for the symmetric stretching