JAMB - Chemistry (2007 - No. 9)
Cu\(^{2+}\)(aq) + 4NH\(_3\)(g) ↔ [Cu(NH\(_3\))\(_4\)]\(^{2+}\)(aq)
In the reaction above, what is the effect of precipitating Cu\(^{2+}\)(aq) as CuS(s)?
In the reaction above, what is the effect of precipitating Cu\(^{2+}\)(aq) as CuS(s)?
NH3(g) concentration will decrease
more NH3(g)
The equilibrium will shift to the right
There will be no effect
توضیح
The precipitation of 
Cu\(^{2+}\) as 
CuS decreases the concentration of 
Cu\(^{2+}\) in the solution. According to Le Chatelier's principle, the equilibrium will shift to the left to counteract this decrease.
Precipitating Cu\(^{2+}\) as CuS shifts the equilibrium to the left, decreasing the concentration of [Cu(NH\(_3\))\(_4\)]\(^{2+}\). Hence more of the reactant will be formed.i.e NH\(_3\)