[wushu093]

Does anybody know the practical use of displacement reactions are?  This is for an assignment i have to do, so i understand it should be in the homework section, but it probably couldnt hurt to put it here seeing as it could be of personal interest to other people as well. any reply is appreciated, so thanks in advance.

[madisonwi]

Well, your question can be interpretted two ways.  

From a pure instructional standpoint, they are essential for learning and understanding stoichiometric relationships in chemical reactions.

From a practical standpoint, displacement reactions (single and double) routinely occur every day.  Many redox equations fall under this realm, as do metals with nitrates exchanging ions and a lot of acid-base reactions.  

Which direction are you looking from?

[wushu093]

im looking for more of a practical use of displacement reactions.

[AWK]

For a long time, before HNO3 was produced on an industial scale, KNO3 needed for gunpowder was produced by a double displacement reaction
NaNO3 + KCl = KNO3 + NaCl
Chile salpetre (from Chile) + potash salt (from Germany)