A potassium dichromate is prepared by dissolving 0.3525 grams of K2Cr2O7 is enough water to yield 250.0 mL of solution. A student then measures 10.00 mL of an unknown solution of Fe2 into an Erlenmeyer flask and dilutes with 90 mL of 1.0 M hydrochloric acid. He then titrates this sample with the solution prepared above. If 38.40 mL of the potassium dichromate solution is needed to reach the end point, what is the concentration of Fe2 in the original unknown solution

Answer asap need by wednesday morning explain how a buffer works, using an ethanoic acid/sodium ethanoate system including how the system resists changes in ph upon addition of a small amount of base and upon addition of a small amount of acid respectively. include the following calculations in your i. calculate the ph of a solution made by mixing 25cm3 0.1m ch3cooh and 40cm3 0.1m ch3coo-na+. [ka = 1.74 x 10-5 m] ii. calculate the ph following the addition of a 10cm3 portion of 0.08 m naoh to 500cm3 of this buffer solution. iii. calculate the ph following the addition of a 10cm3 portion of 0.08 m hcl to 200cm3 of the original buffer solution.