Answer :
Final answer:
The correct answer is B) 1. The number of protons giving rise to the signal at 5 ppm in the 1H NMR spectrum of a compound with the formula C5H10O2 is one proton.
Explanation:
The correct answer is B) 1. The student has asked to determine the number of protons giving rise to the signal at 5 ppm in the 1H NMR spectrum of a compound with the molecular formula C5H10O2. The signal in question is a quintet at 5.0 ppm with an integration value of 6.33. In NMR spectroscopy, the integration value indicates the relative number of protons represented by a signal.
To find the actual number of protons, we need to compare the integration values of all signals and identify the smallest integration value that represents a single proton. The smallest integration value here is the singlet at 2.0 ppm, which represents 19.4 protons. Since we know there are only 10 protons in the molecule, this number is too large and must be divided by a number to bring it down to a reasonable figure (ideally 1, 2, or 3 protons for simplicity in a small molecule spectrum). If we divide all integration values by the same number to maintain the ratio and get an integral number of protons, dividing by 6.33 converts the 6.33 integration value to 1 proton. Therefore, the signal at 5 ppm represents one proton.
