How many mL of 0.05 M sodium acetate should be added to 100 mL of 0.05M acetic acid to make a buffer of pH 5.1? What is the molarity of the resulting buffer with respect to acetate (Acetate + Acetic Acid)? pKa acetic = 4.76

Explanation:

Let us assume that volume of acetic acid added is V ml.

So,  

and,  

Expression for the buffer solution is as follows.

     pH =

     5.1 =

         0.34 = log V - 2

         log V = 2.34

or,        V = 218.77 ml

Now, we will calculate the molarity of the buffer with respect to acetate as follows.

  =

  =

  = 0.0499 M

or,  = 0.05 M (approx)

Thus, we can conclude that molarity of the resulting buffer with respect to acetate is 0.05 M.

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.