Question

1. Clearly and carefully EXPLAIN how each of the following errors will affect the calculated percent ion in your known (higher, lower, not affected).

a) Some of the KMnO4 solution decomposed between the time you standardized it and the time you used it in your determination of iron.

b) Your buret leaked during the permanganate-iron titration and some of the solution spilled onto the lab bench.

c) You did not stop the titration until the solution in the flask was dark purple.

d) You added 118 mL of distilled water to the flask containing the iron salt before the titration, instead of the 100 mL called for.

Answer 1

a ) some KMnO4 solution decomposed means The titrating solution will be at a lower concentration than the desired concentration, so more of the titrant will be needed to reach the end point. The result willbe "HIGHER "

b )  Your buret leaked during the permanganate-iron titration and some of the solution spilled onto the lab bench

means becuase of leak more titrant will b needed so result will be HIGHER

c )  You did not stop the titration until the solution in the flask was dark purple

means you hav added much more titrant so the resulted rror would be HIGHER

d ) You added 118 mL of distilled water to the flask containing the iron salt before the titration, instead of the 100 mL called for

Although the solution is more dilute, you did not change the total amount of iron salt present; therefore, the same amount of titrant will react to the end point. The result is "NOT AFECTED ".