What is whst is the percent yield of so3 in this experiment if 7.9 gram oc so3 are isolated

When the ionic compound nabr dissolves in water, br– ions are pulled into solution by the attraction between what two particles? a. the na+ and br– ions b. the na+ ion and the negative end of a water molecule c. the br– ion and the positive end of a water molecule d. the br– ion and the negative end of a water molecule