In this example question, it says based on the chart shown above, determine which of the following substances will be soluble in water. So in the first one we have hydroxide. Hydroxide can be soluble if it is connected to CBS, Calcium, Barium or Strontium. Here aluminum is not part of CBS. Aluminum is not part of Ghana Cash. Therefore, this is going to stay a solid.
Next we have phosphate and zinc. Now phosphate doesn't have any exceptions from the chart up above. Also Ghana Cash is not involved here because remember we have to take into consideration Ghana cache. Depending on what they're connected to, they could have made this soluble. So here this is not going to be soluble.
Next we have silver with carbonate. Carbonate doesn't have any exceptions. From the chart up above, silver is not part of Ghana Cash, so this will stay as solid. Next we have sulfide ion. Here it's connected to calcium. Remember sulfide has exception CBS. If it is connected to calcium, barium or strontium, it can be soluble. This would be soluble then.
And then finally we have Magnesium with Chromate ion. So chromate doesn't have exceptions from the chart up above. Magnesium is not part of Ghana Cash, so this would not be soluble. It would stay insoluble. So out of the choices given, only option D would create a soluble ionic solute.