Chemistry questions

One ammonium-ammonia buffer is made by dissolving 0.15 mole of NH4 Cl and 0.25 mole of NH3 in water so that the total volume of the solution becomes 200 mL. 

 

a) Calculate the pH of the buffer 

b) Calculate the pH of 100mL of buffer after addition of 10 mL 1 M HCL 

c) Calculate the pH of 100 mL of buffer after addition of 5 mL 1 M NaOH.

 

Task 2.1.9

Calculate the pH of a buffer containing 

 

a) the same amount of substance H2PO4-= 7.2. 

b) 12.2 g of benzoic acid (C6H5COOH) and 7.2 g sodium benzoate (C6H5COOH) = 4.2. 

c) 12.2 benzoic acid (C6H5COOH) and 7.2 g sodium benzoate (C6H5COONa) in 1000 mL solution.

 

2.1.10

Sodium hypochlorite, NaCLO, the active ingredient in many bleaches. Calculate the ratio of [CLO] and [HClO] in a solution where the pH is adjusted to pH = 6.5. pKa (HClO) = 7.5

 

2.1.11

In an intimate soap is pH adjusted to 4.0 with lactic acid and the corresponding salt sodium lactate. What is the most of in the soap, lactic acid or lactate? pKa (lactic acid) = 3.86.