Question

Potassium hydrogen phthalate is a solid, monoprotic acid frequently used in the laboratory to standardize strong base solutions. It has the unwieldy formula of KHC8H4O4. This is often written in shorthand notation as KHP. How many grams of KHP are needed to exactly neutralize 32.0 mL of a 0.332 M calcium hydroxide solution ?

What volume of a 0.232 M calcium hydroxide solution is needed to exactly neutralize 3.54 grams of KHP ?

Answer 1

The balanced reaction between KHP and Ca(OH)2 is
2 KC8H5O4 + Ca(OH)2 >> Ca( KC8H4O4 )2 + 2 H2O

1mole of Ca(OH)2 requires 2 mole of KHP for complete neutralization

moles of Ca(OH)2 in 32 ml of 0.332M = Molarity* volume in L= 0.332*32/1000 =0.011

moles of KHP reqiored =2*0.011=0.022

molar mass of KHP= 204.2 g/mole

mass of KHP = moles* molar mass =4.5 gm

moles of KHP in 3.54 gm= 3.54/204.2=0.017

moles of Ca(OH)2 =0.017/2= 0.0085, volume of Ca(OH)2= 0.0085/(0.232) L=0.04L= 40ml