Respuesta :
Answer:
Volume of HCl = 0.0688 L
Explanation:
pH is defined as the negative logarithm of the concentration of hydrogen ions.
Thus,
pH = - log [H⁺]
So, pH = 1.3
Thus, 1.3 = - log [H⁺]
[H⁺] = 0.05012 M
Since, HCl is a strong acid, the concentration of HCl = 0.05012 M
Also,
Moles of [tex]Mg(OH)_2[/tex]:-
Mass = [tex]4.00\times 10^2\ mg[/tex]
Also, 1 mg = 0.001 g
So =, Mass = [tex]0.4\ g[/tex]
Molar mass of [tex]Mg(OH)_2[/tex] = 58.32 g/mol
The formula for the calculation of moles is shown below:
[tex]moles = \frac{Mass\ taken}{Molar\ mass}[/tex]
Thus,
[tex]Moles= \frac{0.4\ g}{58.32\ g/mol}[/tex]
[tex]Moles_{Mg(OH)_2}= 0.0069\ mol[/tex]
According to the reaction:-
[tex]Mg(OH)_2 + 2 HCl\rightarrow MgCl_2 + 2 H_2O[/tex]
1 mole of [tex]Mg(OH)_2[/tex] neutralizes 2 moles of HCl
Considering:
[tex]Molarity=\frac{Moles\ of\ solute}{Volume\ of\ the\ solution}[/tex]
So,
[tex]Moles =Molarity \times {Volume\ of\ the\ solution}[/tex]
Thus,
[tex]Moles_{Mg(OH)_2}=2\times Molarity_{HCl}\times Volume_{HCl}[/tex]
Appyling values as:-
[tex]0.0069=2\times 0.05012\times Volume_{HCl}[/tex]
Volume of HCl = 0.0688 L
