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A student took 100 ml of a solution of mg(oh)2 and reacted it with h2so4 (aq) to calculate the concentration of hydroxide ions in the solution. if 13.75 ml of 0.010 m h2so4 was used to react with all of the oh- (aq) in the 100-ml solution, what was the concentration of hydroxide ions dissolved in the 100-ml solution

Respuesta :

Mg(OH)₂ + H₂SO₄ → MgSO₄ + 2H₂O

c(OH⁻)-?
v₁=100 mL
c₂=0.010 mmol/mL
v₂=13.75 mL

Mg(OH)₂ → Mg²⁺ + 2OH⁻
c(OH⁻)=2c₁

n{Mg(OH)₂}=n{H₂SO₄}
n{Mg(OH)₂}=c₁v₁=c(OH⁻)v₁/2
n{H₂SO₄}=c₂v₂

c(OH⁻)v₁/2=c₂v₂

c(OH⁻)=2c₂v₂/v₁

c(OH⁻)=2×0.010×13.75/100=0.00275 mmol/mL = 2.75×10⁻³ mol/L

2.75×10⁻³ mol/L