Repaint a fox

Probably, there is no such a schoolboy who would not have read with enthusiasm the remarkable fairy tale of I.Ya. Franco "The painted fox". It turns out, to repaint a fox it is possible and without paint.

Probably, there is no such a schoolboy who would not have read with enthusiasm the remarkable fairy tale of I. Ya. Franco: the painted fox. It turns out, to repaint a fox it is possible and without paint

An experience. On a thick white paper, draw a fox and cut out the drawing with scissors. In a beaker, a saturated solution of K2Cr2O7 in dilute H2SO4. White fox completely immersed in this solution - it becomes red. The wet fox is thrown into a large beaker, filled with gaseous SO2 before the time. The stuffy sulfur gas acts on the red fox and it quickly turns blue or blue. Such a metamorphosis is due to the oxidation-reduction transformation. This produces a chromo-calcium galloon:

K2Cr2O7() + 3SO2 + 2SO4 + 232O = 2Cr(SO4)2*122O().

The most easily sulfuric gas can be obtained due to the interaction of concentrated H2SO4 with copper chips or Na2SO3 (slightly moistened with water). The reactions are carried out under mild heating:

u + 22SO4 = uSO4 + 22O + SO2;

N2SO3 + 22SO4 = 2NSO4 + 2O + SO2.

Tools