Post a New Question

Chemistry

posted by .

Hi everyone,

I have been trying to figure out this titration equation all day and for some reason I am stumped.

Here is the question in full:
Potassium hydrogen phthalate, KHP, can be obtained in high purity and is used to determine the concentrations of solutions of strong bases. Strong bases react wiht the hydrogen phthalate ion as follows:
HP- (aq) + OH- = H2O (l) +p2- (aq)

The molar mass of KHP is 204.2 g/mol and Ka for the HP- ion is 3.1 x 10^-6.

The Questions are: (a) If a titration experiment begins with 0.4885 g of KHP and has a final volume of 100ml, what is the ph of the equivalence point?

(b) If the titration required 38.55ml of NaOH solution to reach the end point, what is the concentration of the NaOH solution?

Thanks for anyone's help and direction with this.

  • Chemistry -

    a.
    mol KHP = 0.4885g/molar mass = ?
    M = mols/0.1 L = approximately 0.024 but you need to do it more accurately.
    At the equivalence point the pH is determined by the hydrolysis of the P^2- ion.
    .........P^2- + HOH ==> HP^- + OH^-
    I.......0.024M...........0.......0
    C..........-x...........x........x
    E.......0.024-x.........x........x

    Kb for P^2- = (Kw/k2 for H2P) = (x)(x)/(0.024-x)
    Substitute all of the numbers and solve for x = OH^-, then convert to pH.
    b.
    mols KHP = 0.4485/molar mass KHP
    mols NaOH = mols KHP (the equation is 1:1)
    M NaOH = mols NaOH/L NaOH. You know mols NaOH and L NaOH solve for M NaOH.

  • Chemistry -

    THANK YOU!

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Inorganic chemistry

    Potassium hydrogen phthalate (molar mass = 204.2g/mol) is used to standardize sodium hydroxide. If 26.37 mL of NaOH(aq) is required to titrate 0.7719g KHP to the equivalence point, what is the concentration of the NaOH(aq) (26.37 mL …
  2. AP chemistry

    A solution of sodium hydroxide is standard- ized against potassium hydrogen phthalate (KHP, formula weight 204.2 g/mol). From the following data, calculate the molarity of the NaOH solution: mass of KHP 1.894 g; buret reading before …
  3. AP Chemistry

    A solution of sodium hydroxide is standardized against potassium hydrogen phthalate (KHP, formula weight 204.2 g/mol). From the following data, calculate the molarity of the NaOH solution: mass of KHP 1.234 g; buret reading before …
  4. Chemistry

    A solution of sodium hydroxide is standard- ized against potassium hydrogen phthalate (KHP, formula weight 204.2 g/mol). From the following data, calculate the molarity of the NaOH solution: mass of KHP 1.654 g; buret reading before …
  5. Chemistry

    A student titrated 1.852 g of a mixture containing potassium hydrogen phthalate, KHP....?
  6. chemistry

    A solution of sodium hydroxide is standard- ized against potassium hydrogen phthalate (KHP, formula weight 204.2 g/mol). From the following data, calculate the molarity of the NaOH solution: mass of KHP 1.744 g; buret reading before …
  7. chemistry

    A solution of the primary standard potassium hydrogen phthalate, KHC8H4O4, was prepared by dissolving 0.4877 g of potassium hydrogen phthalate in about 50 mL of water. Titration with a KOH solution required 17.65 mL to reach a phenolphthalein …
  8. CHEMISTRY

    a solution of sodium hydroxide is standardized against potassium hydrogen phthalate (KHP, formula weight 204.2 g/mol). From the following data, calculate the molarity of the NaOH solution: mass of KHP 1.404 g; buret reading before …
  9. Chemistry

    A solution of the primary standard potassium hydrogen phthalate, KHC8H4O4, was prepared by dissolving 0.4877 g of potassium hydrogen phthalate in about 50 mL of water. Titration with a KOH solution required 24.71 mL to reach a phenolphthalein …
  10. Chemistry

    The concentration of a certain sodium hydroxide solution was determined by using the solution to titrate a sample of potassium hydrogen phthalate (abbreviated KHP). KHP is an acid with one acidic hydrogen and a molar mass of 204.22 …

More Similar Questions

Post a New Question