Lecture
Pour 1–2 cm3 of alkali solution into a test tube, then add a few drops of copper(II) sulfate solution. Add the aldehyde solution given to you to the resulting mixture. Heat the contents of the test tube using a spirit lamp. A yellow precipitate first forms in the test tube, which then turns brick-red.
Write the equations of the reactions taking place and explain the observed phenomena.
Note that an excess amount of copper(II) sulfate leads to the formation of an excess amount of copper(II) hydroxide, which decomposes on heating to form a black precipitate of CuO, so the effect of copper reduction becomes imperceptible against this background.
Comments