A problem in ionic equilbrium

[vijayramakrishnan]

Homework Statement

please see the attached image

1998 ,b part question
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Homework Equations

none

The Attempt at a Solution

i thought that Agcl would give Ag⁺ and cl^- ions whose concentration can be found from K_sp as √K_sp,this Ag⁺ reacts with NH₃ to give Ag(NH₃)₂⁺ (reverse of the given reaction) since K_c of the reaction is given we can find concentration of Ag(NH₃)₂⁺ from it which is K_c= [Ag(NH₃)₂⁺]/[Ag⁺][NH₃]²

but answer obtained is not matching, is the method correct ?,please help.

 

[Borek]

It is not clear to me whether 1M ammonia is the final concentration, or added concentration (in which case some of the ammonia would be consumed).

Your approach is OK in the first case, can be wrong in the latter.

 

[vijayramakrishnan]

It is not clear to me whether 1M ammonia is the final concentration, or added concentration (in which case some of the ammonia would be consumed).

Your approach is OK in the first case, can be wrong in the latter.

sir it is the initial concentration i suppose

 

[Borek]

Then you need to take the reaction stoichiometry into account (simplest approach: an ICE table).

 

[vijayramakrishnan]

Then you need to take the reaction stoichiometry into account (simplest approach: an ICE table).

oh i think i made a mistake concentration of ammonia in initial state is 1 M not the equilbrium concentration,sir are the rest of steps correct?

 

[Borek]

As I told you:

Your approach is OK in the first case, can be wrong in the latter.