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1) What is the concentration of HCl in the final solution when diluted with pure

ID: 591706 • Letter: 1

Question

1) What is the concentration of HCl in the final solution when diluted with pure water to a total volume of 0.15 1? 2) How many milliliters of a 9.0 M H2504 solution are needed to make solution? 0. 45 L of a 3.5 M 3) 6.74 g of the monoprotic acid KHP (MW 204.2 g/mol) is dissolved into water. The sample is titrated with a 0.703 M solution of calcium hydroxide to the equivalence point. What volume of base was used? (Hint: If a little stuck, or needing a start, go to problem 4 first! It breaks it all down!)

Explanation / Answer

1. before dilution                             after dilution
    M1 = 9M                                       M2 =
    V1 = 65ml                                     V2 = 0.15L = 150ml
             M1V1   = M2V2
               M2   = M1V1/V2
                    = 9*65/150   = 3.9M
The conc of HCl = 3.9M
2.
    before dilution                           after dilution
    M1 = 9M                                    M2 = 3.5M
    V1 =                                      V2 = 0.45L = 450ml
             M1V1    =    M2V2
                V1   =    M2V2/M1
                     =    3.5*450/9   = 175ml >>>answer

3. 2KHP + Ca(OH)2 -----------> Ca(KP)2 + 2H2O
   2 mole 1 mole
   no of moles of KHP = W/G.M.Wt
                       = 6.74/204.2 = 0.033 moles
   2 moles of KHP react with 1 moles of Ca(OH)2
   0.033 moles of KHP react with = 1*0.033/2 = 0.0165 moles of Ca(OH)2
   no of moles of Ca(OH)2 = molarity * volume in L
         0.0165            = 0.703* volume in L
      volume in L           = 0.0165/0.703 = 0.0235 L = 23.5ml >>>>answer