The compound magnesium iodide is a strong electrolyte write the reaction when solid magnesium iodide is put into water

  The  reaction  for magnesium  iodide  when put into water  is  as below

 MgI2(s) →  Mg^2+(aq)   + 2I^-(aq)

when  magnesium iodide  but into water it dissociate/ ionize  completely  into  Mg^2+  and  2l^-   ions. Magnesium iodide dissociate/ionize  completely because  magnesium  iodide  is a strong electrolyte  which  dissociate/ ionize  completely into their ions  when it is put into   water .