Question

Predict and balance each of the following equations. If no reaction occurs, write NO REACTION. Just give the Complete Molecular formula. a). ____SrCl2 (aq) + ___NH4Cl (aq) can someone explain to me how to predict and balance step-by-step please? How to balance and predict in general. Not just this question

Answer 1

Q)

SrCL2(aq) + NH4Cl(aq) ------------> No reaction

The common idea of predcting a reaction occurs when two aqueous solutions are mixed is

i) look for a formation of precipitate.

If the combination of two ions from differents salts in solution forms a precipitate, there is a reaction.

If all the ions remain in solution there is no reaction.

Now in the above example why there is no reaction, as SrCl2 is soluble in water (you took aqueous soltion), the other anion is also Cl- , no precipitate from Sr+2 . On the other salt NH4+ ion. All ammonium salts are soluble in water . so no precipitation.

THat means all ions rmain in water as it is like Sr+2, NH4+ ,Cl- .

So you dont see any reaction.

example 2.

AgNO3(aq) + NaCl(aq) ------------> AgCl(s) + Na+ + NO3

Here when you mix these two solutions, the Ag+ from one salt and Cl- from other start forming an insoluble AgCL product , thus we notice a white precipitate formed.

Na+ and NO3- still remain as it is in water.

ii) If there is a gas produced in the reaction

CaCO3 + HCl -----------> CaCl2 + H2O + CO2(g)

Here though caCl2 is water soluble , that means Ca+2 and Cl- remain in solution, still you see evolution of gas.

Thus raction is done.