analytical practice problems

Q1: How many grams of dipotassium phtalate (MW = 242.31 g/mol) should be added to 30.00 mL of 0.400 M HClO₄ to give a pH of 5.10 when the solution is diluted to 500 mL?

 

 

Q2:  What is the pOH of:

(a)   a 0.0100 F solution of phtalic acid?

(b)   a 0.0100 F solution of monopotassium phtalate?

(c)    a 0.0100 F solution of dipotassium phtalate?

 

if pK_a1 = 2.950 and pK_a2 = 5.408 for phtalic acid.

 

 

Q3:  Calculate the volume of 0.150 M NaOH titrant added to 50.00 mL of a 0.0100 M HCl analyte solution to produce a pH of: 2.00, 2.11, 7.00, and 11.60.

 

 

Q4:  A 100.0 mL solution of 0.5 M histidine in its tribasic form, A^3-, (pK_a1 = 1.70, pK_a2 = 6.02, pK_a3 = 9.08) is titrated with 1.0 M HCl titrant.

(a)   calculate the volume of titrant required to reach the second equivalence point,

(b)   calculate the pH after the addition of 50.0 mL of titrant,

(c)    calculate the pH after the addition of 62.0 mL of titrant,

(d)   calculate the pH after the addition of 75.0 mL of titrant.

 

 

Q5:  A 100 mL volume of a 0.100 M weak base (pK_b = 5.00) was titrated with 1.00 M HClO₄.  Find the pH at the following volumes of added acid:  0.00, 1.00, 5.00, 10.00, and 10.10 mL.

 

 

Q6:  A 100.00 mL volume of 0.0400 M propionic acid (CH₃CH₂COOH; K_a = 1.34 ´ 10^-5) was titrated with 0.0837 M NaOH.  Calculate the pH after the addition of: 0 V_e, 0.25 V_e, V_e, and 1.1 V_e mL of titrant where V_e is the volume of NaOH required to reach the equivalence point.