highest percentage of gold by weight can be determined by looking at the atomic mass of the other elements in the compound. the smaller the total of mass of the other elements, the heigher the percentage of Au will be in that compound
a. AuOH, OH- = 17 gram/mole
b. Au(OH)3, 3 x OH- = 3 x 17 = 51 gram/mole
c. AuCl3 = 3x35.5= 106.5 gram/mole
d. AuI3 = 3x127 = 381 gram/mole
as we can see AuOH has the least Molecular mass, hence % of Au will be the highest compared to other choices
Answer: A