'A' Level Qn.
M has formula C13H16O. it decolourises aq bromine and produce white fumes with PCl5. it reacts with hot KMnO4 to produce N (C8H8 O), P (C3H2O5) and Q (C2H4O2). N does not react with fehling but react with aq alkaline iodine to give yellow ppt + salt R (C7H5O2Na). P gives effervescence with solid sodium carbonate and gives orange ppt with dinitrophenylhydrazine. Q gives effervescence with solid sodium carbonate but no ppt with dinitrophenylhydrazine. identify M N P Q R.
Answer :
N - CH3 CO C6H5
P - HOOC CO COOH
Q - CH3 COOH
M - C6H5 C (CH3) = C (CH2OH) CH = CH CH3
With the answers provided, just give the question a try. Such questions are interesting but i'm too lazy to work it out.
Use the test to determine the number of double bonds, their position, type and position of O etc etc.
Start with the smallest which is Q, you know its an acid since it reacts with Na2CO3 and there is only 1 acid you can form with that formula..
P reacts with carbonates as well so you do expect another acid and with such a low number of C, you might expect a diacid and with the dinitrophenylhydrazine test, determine the structure.
For N, what does fehling test and iodine test tells you? Looking at the number of C and H, it would be too little H for alkyl chains so a good guess would usually be a benzene ring.
With that 3, you can try to piece them together to get your M with the tests done.