The reason for the trend in the previous question is because Bromine is electron density from the carbon the proton is on, resulting in the proton being , thus the proton nuclei is effected by the applied magnetic field leading to a greater difference in energy of the nuclei's spin states.

Explanation:

From this question, we are to fill in the blanks with the appropriate correct answers.

NOTE: that the electron-withdrawing groups decrease the electron density around the proton nucleus and therefore the nucleus feels the external magnetic field more. Hence, it requires a larger frequency to attain resonance(downfield).

a

gasoline is a mixture. it contains several different kinds of compounds that can be present in a variety of ratios.