A solution holds 0.0200 mol of benzenediazonium chloride…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A solution holds of benzenediazonium chloride. It is added to a mildly alkaline solution of phenol, (), and p-hydroxyazobenzene, , forms. Use C = 12, H = 1, N = 14 and O = 16 in g/mol. Find the molar mass of the dye and the mass of dye at a yield of 100 %. Then find the mass collected at a yield of 75 %. Last, find the mass of phenol needed in the exact amount.
Need a reminder? The key ideaShow
Coupling joins the diazonium ion to the para position of a phenol or an aromatic amine through an azo group, . The coupling partner reacts in its deprotonated form: the phenoxide ion or the free amine. The fraction in that form is . For an indicator, .
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. Molar mass. .
Step 2. At 100 %. .
Step 3. At 75 %. .
Step 4. Phenol. .
Answer: , , and .
Check. The dye is the sum of the two rings, () and (), which is .
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