Suppose your lab instructor inadvertantly gave you a sample of KHP contaminated with NaCl to standardize your NaOH. How would this affect the molarity of your NaOH solution?
I was thinking that since NaOH + NaCl -------> NaCl + NaOH (??), then the molarity would not be affected...but this doesn't seem right...could anyone point me in the right direction? Thank you!!!
2006-10-25 09:34:53 · 2 answers · asked by Anonymous in Science & Mathematics ➔ Chemistry
It would increase the apparent molarity, due to the NaCl acting as a non-reactive impurity.
eg, assume that 1.00g KHP would require 20ml of your NaOH soln...but that your KHP was contaminated wih 10% NaCl...you would be titrating against only 0.90g KHP, which would take only 18ml to complete neutralization....indicating that the NaOH is stronger than it acually is.
A question like this can be tricky...you must think it through.
2006-10-25 13:22:03 · answer #1 · answered by L. A. L. 6 · 0⤊ 0⤋
If you are titrating the OH- with KHP, it won't matter about the NaCl. As you correctly identified, the chloride and hydroxide salts of sodium do not interact, and therefore the titration reaction will not be effected by the NaCl.
It won't actually affect the molarity, anyway... it would only effect your measurement of it :)
Are you sure it was inadvertant? If it isn't supposed to be there, just ask for a differentsolution of KHP.
2006-10-25 09:40:38 · answer #2 · answered by Elizabeth S 3 · 0⤊ 0⤋