If 38.91 mL of a barium hydroxide solution are needed to neutralize 2.373 grams of KHP, what is the concentration (mol/L) of the barium hydroxide solution?

Question

Potassium hydrogen phthalate is a solid, monoprotic acid frequently used in the laboratory as a primary standard. It has the unwieldy formula of KHC₈H₄O₄. This is often written in shorthand notation as KHP.

If 38.91 mL of a barium hydroxide solution are needed to neutralize 2.373 grams of KHP, what is the concentration (mol/L) of the barium hydroxide solution?

Answer 1

First balance equation: 

Ba(OH)₂ + 2KHC₈H₄O₄ -> 2H₂O + Ba(KC₈H₄O₄)₂

1 mole of Ba(OH)₂ to 2 moles KHP

moles of KHP= 2.373/(40+1+8*12+4*1+4*16) = 0.01158 moles

Divide by 2 to get moles of Ba(OH)₂

0.01158/2 = 0.005788moles of Ba(OH)₂

Divide by volume to get M (convert mL to L)

0.005788/0.03891 = 0.149M