Answer:
No, no precipitate is formed.
Explanation:
Hello there!
In this case, since the reaction between ammonium sulfide and aluminum nitrate is:
[tex]3(NH_4)_2S(aq)+2Al(NO_3)_3(aq)\rightarrow Al_2S_3(s)+6NH_4NO_3(aq)[/tex]
In such a way, we can calculate the concentration of aluminum and sulfide ions in the solution as shown below, and considering that the final total volume is 140.00 mL:
[tex][Al^3^+]=\frac{120.00mL*0.0082M}{140.00mL}=0.00703M[/tex]
[tex][S^2^-]=\frac{20.00mL*0.0090M}{140.00mL}=0.00129M[/tex]
In such a way, we can calculate the precipitation quotient by:
[tex]Q=[Al^3^+]^2[S^2^-]^3=(0.00703)^2(0.00129)^3=1.05x10^{-13}[/tex]
Which is smaller than Ksp and meaning that the precipitation does not occur.
Regards!