1. Assume you were given a solution that was said to contain Ca^2+ cations only.

Question

1. Assume you were given a solution that was said to contain Ca^2+ cations only. Describe how you would confirm or deny the presence of this cation in the solution. Explain your reasoning.

2. Assume you were given a solution that was said to contain Zn^2+ and Al^3+ cations only. Describe how you would determine if neother, only one, or both of these ions were present in solution. Explain your reasoning.

3. Assume you were given a solution that was said to contain Cu^2+ and Co^2+ cations only. Describe how you would determine if neother, only one, or both of these ins were present in solution. Explain your reasoning.

Please explain, thank you.

Explanation / Answer

1. If the solution contained only Calcium ions, it should give the following positive test::

When the solution is treated with sodium hydroxide, insoluble calcium hydroxide is formed. So a white precipitate will be formed which is not soluble in excess NaOH.

No precipitate is also formed with ammonia solution.

Taking the formed precipitate and using the flame test should give a brick red color if the calcium ion is present.

If all three are confirmed, it confirms the presence of calcium cation

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