Predict whether a precipitation reaction will occur when aqueous solutions of the following substances are mix?

3 Answers

• MnCl_2 +Na_2S -----> 2NaCl + MnS(ppt)

  2HNO_3 +CuSO_4-----> H2SO4 + Cu(NO3)2 (no ppt)

  Substances which are insoluble are ppt

  Now,

  Salts of Na K and NH3 are always soluble so no ppt

  All nitrates,bicarbonates,sulphates,chlorides are soluble

  so all other substances like oxides and carbonates are insoluble

  NOTE : ALL SALTS of NA K AND ammonia are soluble

  REST ALL WILL FORM PPT's

• To tell if there will be a precipitate, you need to look at the components of the two substances you are mixing, and then switch them to a different combination like this:

  You start with Mn Cl and Na2S

  Recombine the ions to get: Mn2S and NaCl. Remember to match up the positive and negatively charged ions, ie dont match up NaMn because they are both positively charged. The first ion listed will be positive, the second is negative

  Now, check your solubility rules. If both of these new substances are soluble, you will NOT have a precipitate. So for this example, Mn2S would preciptate, because it is insoluble.

  Here is a great list of solubility rules: http://www.ausetute.com.au/solrules.html

  Looking at the rules for the sulfide ion, you see a list of cations (positive charge) with which it will be soluble (no precipitate), and it says that for all other cations it is insoluble. If it is insoluble, it will form a solid (precipitate from the solution). You can look at the same information for the Cl- anion, and you will see that NaCl would be soluble, so it would not precipitate.

  Good luck!

• A. SrSO4(s) + H2(g) + 2NO3(g) B. 2Na(NO3)(aq) + ZnSO4(s) C. No reaction D. NO reaction (they both remain aqueous)