Solution Investigation Question: What are some of the key characteristics of unk

Question

Solution Investigation Question: What are some of the key characteristics of unknown sample of an aqueous solution containing an ionic compound?

Specific questions:

1. Given that the cation is from Group 1A, what is the identity of the group 1A metal ion in your solution?

2. Given that the ionic compound contains either chloride or hydroxide, how can you determine which? (Two pieces of evidence are required and one must be related to solubility rules)

3. What is the concentration of your solution? (Your unknown sample is known to be about 1 M, but you need to determine the concentration to 3 significant figures using titration. You should plan ahead so that you know approximately what volume of your sample you will need in order to use approximately 25 mL of 0.100 M sulfuric acid for the titration).

What I am trying to determine is what method or how can I answer these question.

Explanation / Answer

1. I need more info such what experiment are you making, and/or procedure. However let me try to help you at least with the first two questions.

If you know that the your unknown is a cation from group 1A, then, all you have to do is the flame test. What do you do? use a Platinum wire, and clean it with a flame several times (Just pass the wire through the flame a couple of times). Then, dop the wire into the solution, and pass it through the flame. If the flame turns a yellow-orange color, then you may actually say that the metal ion is the Sodium (Na). If it turns in another color, then you have another metal (like potassium).

2.  you need to add one of the dropper bottle solutions given to see if a precipitate forms. Since we know it's OH we need to drop in a solution which will have a double replacement reaction. If the product is insoluble, its OH. If not, it's Cl. But obviously it's OH because we are titrating. In this case, you may use an acid, and see if you form a precipitate of a salt. With this you may know if you have a OH (All hidroxides of group 1 are soluble). If it's not, then you probably have a Cl. However, like I stated before, we can have a clue of an OH because in the next step you begin to titrate so, it's an OH.

Hope this helps you a little.

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