Use the Redervaces to access impertane values if aeeded for thih qurstion A stud
ID: 1036701 • Letter: U
Question
Use the Redervaces to access impertane values if aeeded for thih qurstion A student is asked to standardize a sobution of calciam hydroxide. He weighs out 0.926 g potassium hydrogen phthalate (KHC,H,O treat this as a monoprotic acid) It requires 16.9 mL of calcium hydroxide to reach the endpoint A. What is the molarity of the calcium hydroxide solution? This calciums hydroxide solution is then used to titrate an unknown solution of perchlerie acld B. If 11.4 mL of the calcium hydroxide solution is required to neutralize 29.3 mL of perchloric acid, what is the molarity of the perchloric acid solution? Ratry Entire Group 9 more group attempts remalining
Explanation / Answer
Ca(OH)2+ 2KHP ( potasium hydrogen phthalate)---------->Ca(KP)2+2H2O
1 mole of Ca(OH)2 requires 2 moles of KHP for complete neutralization.
moles of potassium hydrogen phthalate = mass/molar mass= 0.926/204.22=0.0045
moles of Ca(OH)2 required =moles of KHP/2=0.0045/2=0.00225
volume of Ca(OH)2 used = 16.9 ml, 1000ml= 1L, 16.9 ml= 16.9/1000L
concentration of KHP= moles/ volume in Liters= 0.00225*1000/16.9=0.133M
The reaction between Ca(OH)2 and perchloric acid (HClO4) is
Ca(OH)2+ 2HClO4 ---------Ca(ClO4)2+ 2H2O
1 mole of Ca(OH)2 requires 2 moles of HClO4
moles of Ca(OH)2 in 11.4 ml= molarity* volume in Liters =0.133*11.4/1000
moles of HClO4= 2* moles of Ca(OH)2 = 2*0.133*11.4/1000
volume of HClO4 given = 29.3 ml = 29.3/1000L
concentration of HClO4= 2*0.133*11.4/1000/29.3/1000 =0.1034M
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