An unknown organic liquid, A, was found to burn with yellow, sooty flame and give a positive Lucas test (about 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 with Tollens reagent. However, B did give a positive iodoform test. The 1H NMR spectrum for Compound A showed the following:
1.4 ppm 3H (doublet)
1.9 ppm 1H (singlet)
4.8 ppm 1H (quartet)
7.2 ppm 5H (complex multiplet)
The expert identifies unknown organic liquids and gives structures.