Which of the following statements are TRUE for first-order analyses of NMR spectra (the type of analysis most commonly done).
1. Carbon-13, an NMR-active nucleus, has a nuclear spin quantum number of 0.
2. The peak multiplicity in a proton spectrum is (n+1), where n is the number of adjacent, equivalent hydrogens.
3. First-order multiplets are symmetrical, and their chemical shift is given by the position of the first peak in the multiplet.
4. The spin-multiplicity of the proton NMR absorption of the methyl group in ethanol-OD is 4.
5. The difference in absorption frequency is equal to or less than 6 J.
6. The peak multiplicity in a proton spectrum is (n+1), where n is the number of adjacent, equivalent hydrogens.