A student carries out an experiment to standardize (determine the exact concentr

Question

A student carries out an experiment to standardize (determine the exact concentration of) a sodium hydroxide solution. To do this the student weighs out a 1.3009-g sample of potassium hydrogen phthalate (KHC8H404, often abbreviated KHP). KHP (molar mass 204.22 g/mol) has one acidic hydrogen. The student dissolves the KHP in distilled water, adds phenolphthalein as an indicator, and titrates the resulting solution with the sodium hydroxide solution to the phenolphthalein endpoint. The difference between the final and initial buret readings indicates that 41.20 mL of the sodium hydroxide solution is required to react exactly with the 1.3009 g KHP. Calculate the concentration of the sodium hydroxide solution.

The answer is 0.1546M

I NEED THE WORK PLEASE. PLEASE SHOW ALL WORK.

Explanation / Answer

The reaction between an acid and base produces salt and water:

NaOH(aq)+KHC8H4O4(aq) = KNaC8H4O4(aq) + H2O(l)

Molarity of KHP=Mass in grams of KHP/ Molar mass of KHP==1.3009/204.22=0.00637M

From the above mentioned chemical equation it is clear that the no.of moles of NaOH and KHP for neutralisation is same i.e. 1:1

Therefore number of moles of NaOH =No. of moles of KHP=0.00637

Molarity of NaOH= No. of moles of NaOH/ Volume in Litres= 0.00637/41.20X10-3 = 0.1546M

Hence concentration of Sodium Hydroxide Solution is 0.1546M

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