The H NMR spectrum of 1, 2, 2-trichloropropane has two peaks other than the TMS peak · How can you ou tell which peak corresponds to the two H, protons and which is from the three H2 protons? Here's a clue: Chlorine atoms are very electronegative and strongly electron withdrawing. Thi means that they suck electron density away from the atoms close to them. The two H, protons are attached to a carbon that is also attached to a chlorine atom. As a result, these protons have less electron density around them, are less effectively shielded, and have a chemical shift further downfield than the H, protons (H=A, H2=B) Integration In addition to chemical shift, the relative size of the peaks provides information When you take a H NMR, you will integrate the different peaks in your spectrum. The relative values of the integrals are proportional to the number of protons absorbing energy at that frequency For example(from above) The spectrum tells you that there is a 3: 2 ratio of different protons in 1, 2, 2-trichloropropane. Of course you know that there are three H, protons and two H, protons that fit this criteria 7H1 H1 H2 H2 C C Cl C H2 Cl Cl • The 1 H NMR spectrum of 1,2,2-trichloropropane has two peaks other than the TMS peak. • How can you tell which peak corresponds to the two H1 protons and which is from the three H2 protons? Here's a clue: Chlorine atoms are very electronegative and strongly electron withdrawing. This means that they suck electron density away from the atoms close to them. • The two H1 protons are attached to a carbon that is also attached to a chlorine atom. As a result, these protons have less electron density around them , are less effectively shielded, and have a chemical shift further downfield than the H2 protons (H1 = A, H2 = B). Integration • In addition to chemical shift, the relative size of the peaks provides information. • When you take a 1 H NMR, you will integrate the different peaks in your spectrum. The relative values of the integrals are proportional to the number of protons absorbing energy at that frequency. For example (from above): B : A = 75 : 50 = 3 : 2 The spectrum tells you that there is a 3 : 2 ratio of different protons in 1,2,2-trichloropropane. Of course you know that there are three H2 protons and two H1 protons that fit this criteria. 7