chemistry question

Question

write the equation for the neutralization reaction of potassium hydroxide and phosphoric acid.then calculate the concentration of a H3PO4 solution if 25 mL of H3PO4 is needed to neutralize 1.306 g of KOH

Answer 1

The balanced equation for this reaction is:

3KOH(aq) + H₃PO₄(aq) ==> 3H₂O(l) + K₃PO₄(aq)

moles KOH = 1.306 g KOH x 1 mole KOH/56.11 g = 0.02328 moles KOH

moles H₃PO₄ = 0.02328 moles KOH x 1 mole H₃PO₄/3 moles KOH = 0.00776 moles H₃PO₄ 

Concentration of H₃PO₄ = 0.00776 moles/0.025 L = 0.3104 M = 0.31 M (to 2 significant figures)