An aqueous solution of hydroiodic acid is standardized by titration with a 0.168 M solution of sodium hydroxide. If 18.7 mL of base are required to neutralize 29.6 mL of the acid, what is the molarity of the hydroiodic acid solution

0.106M

Explanation:

Equation of reaction

NaOH + HI = ==" NaI + H₂O

If 0.168 moles of NaOH = 1000cm³

X moles = 18.7 cm³

X = (18.7 * 0.168) / 1000 = 0.00314 moles

From equation of reaction,

1 moles of NaOH = 1 mole of HI

0.00314 moles of NaOH = 0.00314 moles of HI

Therefore,

0.00314 moles of HI = 29.6cm³

X moles = 1000cm³

X = (0.00314 * 1000) / 29.6 = 0.106M