Question

How would the following experimental errors change the calculation of the number of mg of ascorbic acid in fresh orange juice? a.Students neglected to filter the juice. (pulp and other solids remain) b.The DCP was standardized properly but it was the previous day c. The student neglected to add the pH 3 buffer. d. The student neglected to add the metaphosphoric acid.

Answer 1

a.Students neglected to filter the juice. (pulp and other solids remain)

there will be much more mass, which will intereferec, the acid + mg will not react so the concnetration will be lower

b.The DCP was standardized properly but it was the previous day

DCP decomposes, so not all 100% will be present, therefore concentration will be lower

c. The student neglected to add the pH 3 buffer.

there is no precipitation range, therefore concentration of Mg will be lower

d. The student neglected to add the metaphosphoric acid.

if no acid is added, there is no reaction, therefore Mg will not precipitate