Question

34.62 mL of a 0.3 M Mg(OH)2 solution are needed to neutralize a 15-mL solution of HCl on unknown concentration. Calculate the concentration of HCl solution.

Answer 1

Mg(OH)₂+2HCl=MgCl₂+2H₂O

1.Trace by finding the amount of Mg(OH)_2. To do this, we multiply the molarity by the volume (liters):

0.03462litres *0.3 mol/litres= 0.010386 mol Mg(OH)₂

2.based on the reaction we find the amount of HCl.that is, HCl is 2 times more than Mg(OH)₂, so multiplying Mg(OH)₂ by 2 gives the amount of HCl: 0.010386*2=0.020472mol

3.Find the concentration of HCl by dividing the amount of substance by the volume (liters): 0.020472mol/0.015 litres=1.3648mol/litres

Answer:1.3648mol/litres