In a titration 32.5 mL of 1.0 M sulfuric acid is required to neutralize 45.0 mL of sodium hydroxide. What is the concentration of the base?

Respuesta :

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Answer:

[tex]\large \boxed{\text{1.4 mol/L}}[/tex]

Explanation:

(a) Balanced equation

2NaOH + H₂SO₄ ⟶ Na₂SO₄ + 2H₂O  

(b) Moles of H₂SO₄

[tex]\text{Moles of H$_{2}$SO}_{4} = \text{32.5 mL H$_{2}$SO}_{4} \times \dfrac{\text{1.0 mmol H$_{2}$SO$_{4}$}}{\text{1 mL H$_{2}$SO$_{4}$}}\\= \text{32.5 mmol H$_{2}$SO}_{4}[/tex]

(c) Moles of NaOH

The molar ratio is 2 mol NaOH:1 mol H₂SO₄.

[tex]\text{Moles of NaOH} = \text{32.5 mmol H$_{2}$SO}_{4} \times\dfrac{\text{2 mmol NaOH}}{\text{1 mmol H$_{2}$SO}_{4}}\\\\= \text{65 mmol NaOH}[/tex]

(d) Molar concentration of NaOH

[tex]c = \dfrac{\text{moles of solute}}{\text{litres of solution}}\\\\c = \dfrac{n}{V}\\\\c= \dfrac{\text{65 mmol}}{\text{45.0 mL}} = \text{1.4 mol$\cdot$L$^{-1}$}\\\\\text{The molar concentration of the NaOH is $\large \boxed{\textbf{1.4 mol/L}}$}[/tex]

Note: The answer can have only two significant figures because that is all you gave for the molar concentration of the sulfuric acid.