A particulate diagram depicts the mixing of equal-volume aqueous solutions of AgNO3 and NaCl. In the “before” boxes, isolated gray spheres (Ag+) are paired with white tripods (NO3−) and light-blue spheres (Na+) are paired with green spheres (Cl−). In the “after” box, the gray and green species are aggregated into clusters that settle, whereas the white tripods and light-blue spheres remain uniformly dispersed in the water.
Which anion present in the system acts as a spectator ion during the chemical change?
a) Cl−
b) OH−
c) NO3−
d) NO2−