Achunk of dry ice, solid co2, "disappears" after sitting at room temperature for a while. there is no puddle of liquid. what happened?

a-the solid co2 sublimed.
b-the solid co2 melted.
c-the solid co2 underwent deposition.
d-the solid co2 underwent fusion.

The activity series is shown in the attached picture. if the element is below the other, then you can displace the other. following the activity series as a guide, the reactions are as follows: nickel and aluminum chloride3 ni + 2 alcl₃  → 3 nicl₂ + 2 albarium and copper bromideba + cubr  →  no reaction because cu is less oxidizable than bapotassium nitrate and aluminum3 kno₃ + al  → al(no₃)₃ + 3 ksodium phosphate and zincnaso₄ + zn  → znso₄ + na

Answer the same molecular formula;