Answer 1) : To calculate the concentration of number of moles of Mg , by dissolving 2.75 X
, by dissolving 2.75 X  of Mg
 of Mg will be like this;
 will be like this;
Number of moles of Mg = (2.75 X
 = (2.75 X  g of Mg
 g of Mg ) X (1 mole of Mg
) X (1 mole of Mg / 95.211 g of Mg
 / 95.211 g of Mg )
)
= 2.88 X  moles of Mg
 moles of Mg (g/L)
 (g/L)
In ppm it will be 0.288 ppm
Answer 2) To find the moles of Mg ions in solution of Mg , we need to find the moles of Mg present in the solution,
, we need to find the moles of Mg present in the solution,
Here, moles of Mg = Moles of Mg
So, 2.88 X  moles of Mg
 moles of Mg = 2.88 X
 = 2.88 X  moles of Mg. (g/L)
 moles of Mg. (g/L)
And in ppm it will be 0.288 ppm
Answer 3) For calculating the moles of Cl ions present in the solution of Mg , we need to know how many moles are present in Mg
, we need to know how many moles are present in Mg ,
,
We see 2 moles of Cl ions are present in solution of Mg 
 
Therefore, 2 moles of Cl = 1 mole of Mg
So, We can multiply 2 with the molarity of Mg , we get,
, we get,
2 X (2.88 X  )= 5.77 X
)= 5.77 X  g/L
 g/L
And in ppm it will be 0.577 ppm.