Question

AB will precipitate when the concentration of \( B^- \) ions is:

• A. between $10^{-8} M$ to $10^{-7} M$
• B. between $10^{-7} M$ to $10^{-8} M$
• C. $> 10^{-5} M$
• D. $< 10^{-8} M$

Hint:

Precipitation occurs if Ionic Product $> K_{sp}$.

Answer 1

The Correct Option is C

Step 1: Concept
Precipitation requires ionic product to exceed $K_{sp}$.
Step 2: Analysis
With $K_{sp} = 10^{-8}$ and $[A^{+}] = 10^{-3}$, $[B^{-}]$ threshold is $10^{-5}$.
Step 3: Conclusion
It precipitates when $[B^{-}]$ is more than $10^{-5} M$.
Final Answer: (C)