Answer:
The concentration of the potassium ions in ppm is 137.5 ppm
Explanation:
Here, we are interested in calculating the concentration of the potassium ions in ppm.
Mathematically, the term ppm which is read as parts per million is = mg of solute/liter of solution
We already have the mg of solute as 55mg
all we need now is the liters of solution
But what we have is 400 ml which is read as 400 milliliters
Mathematically, 1000 ml = 1l
Thus 400 ml = 400/1000 L = 0.4 L
Now the ppm = 55mg/0.4L = 137.5 mg/L or simply 137.5 ppm