The largest number of anions is formed during the complete dissociation of 1 mol of 1) aluminum nitrate;

The largest number of anions is formed during the complete dissociation of 1 mol of 1) aluminum nitrate; 2) sulfuric acid; 3) sodium phosphate; 4) barium hydroxide

When dissolved in water, electrolytes decompose into ions: cations – charge (+) and anions – charge (-).
Aluminum nitrate – Al (NO3) 3 = Al (3+) + 3 NO3 (-) – 1 mol of aluminum cations, 3 mol of nitrate anions);
Sulfuric acid – H2SO4 = 2H (+) + SO4 (2-) – 2 mol of hydrogen cations, 1 mol of sulfate anions);
Sodium phosphate – Na3PO4 = 3Na (+) + PO4 (3-) – 3 mol of sodium cations, 1 mol of phosphate anions);
Barium hydroxide – Ba (OH) 2 = Ba (2+) + 2 OH (-) – 1 mol of barium cations, 2 mol of hydroxide anions).
Answer: aluminum nitrate.