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 with the Tollens reagent. However, compound B did give a positive iodoform test. The 1H NMR spectrum for compound A showed the following:

1.4 ppm 3H (doublet) 4.8 ppm 1H (quartet)

1.9 ppm 1H (singlet) 7.2 ppm 5H (complex multiplet)

Give the structures and suitable names for compounds A and B.