Ethanal is made in two steps from calcium carbide…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
Ethanal is made in two steps from calcium carbide. First, of pure calcium carbide, with a molar mass of , reacts with water to give ethyne, with a yield of . Then the ethyne is passed into dilute sulphuric acid with mercury(II) sulphate at , where it forms ethanal with a yield of . The molar mass of ethanal is .
Find the moles of ethyne formed and the mass of ethanal collected.
Need a reminder? The key ideaShow
Ozonolysis with zinc and water cuts C=C: gives methanal, an aldehyde and a ketone. Hot acidified permanganate gives carbon dioxide, an acid and a ketone. A terminal alkyne has an acidic hydrogen and gives precipitates with ammoniacal silver or copper(I). Hydration of an alkyne gives a ketone, or ethanal from ethyne.
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. The equations. and . Each step is one mole for one mole.
Step 2. Carbide. .
Step 3. Ethyne. .
Step 4. Ethanal. . The mass is .
Answer: of ethyne and of ethanal.
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