Question

Splitting of a signal in a proton NMR spectrum tells us the number of chemically non-equivalent hydrogens in the immediate vicinity of the hydrogen giving the signal. Predict the number of lines exhibited by hydrogens at the labeled positions in a first-order NMR spectrum. (Make the approximation that all coupling constants are equal.) The number of lines exhibited by hydrogen(8) a is The number of lines exhibited by hydrogen(s) b is The number of lines exhibited by hydrogen(s) e is 2) The number of lines exhibited by hydrogen(s) a is The number of lines exhibited by hydrogen(s) b is The number of lines exhibited by hydrogen(8) c is

Answer 1

a In 1H NMR total number of lines exhibits by hydrogen(s) is = total number of H present in its neighbor +1 In this compound in hydrogen on 'a' will show one line (singlet) as the neighboring carbon does not contain any H. Hydrogen on 'b' will show seven lines (septet) as the neighboring carbon contains 6H (3H+3H). Hydrogen on 'c' will show two lines (doublet) as the neighboring carbon contains 1H. C clayo In this compound Hydrogen on 'a' will show three lines (triplet) as the neighboring carbon contains 2H. Hydrogen on 'b' will show five lines (quintet) as the neighboring carbon contains 4H. Hydrogen on 'c' will show five three (triplet) as the neighboring carbon contains 2H. NB: For your better understanding I have attached predicted NMR spectrum of both the compounds. Please check the attached files.

| g, -4 72 7.0 6.8 6.6 6.4 6.2 6.0 5.8 5.6 5.4 5.2 5.0 4.8 4.6 4.4 .48 4.0 3.8 3.6 3.4 3.2 3.0 28 2.6 24 2.2 2.0 1.8 1.6 1.4 1.2 1.0

ܕܐ 8ܐ ܕܐ ܘܐ 4ܕܐ ܕܐ ܐܐ 1ܐ 19 ܓܘܐ 18 17 16 15 14 13 12 11