run something into something. 1. to guide or route something, such as a wire or a pipe, into something or a place. The worker ran the circuit into each room. He ran in the circuit as specified. 2. to guide something into something; to drive or steer something into something else.
A change of color to a blue-black or purple color suggests that starch is present. If there is no change in color, this suggests no starch is detectable. Note the change of the iodine to black on the potato (right) but not the apple (left). (10% Tincture of iodine.) Potato contains starch, but apple does not.
The reactions involve the oxidation of iodide ion (I-) to dissolved iodine (I2) or tri-iodide ion (I3-). Either of these combine with starch indicator to produce the characteristic purple-blue color. This color is visible to the eye when the concentration of iodine or tri-iodide ion exceeds 10-5 moles/liter. A typical reaction is: 6 H+ + IO3- + 8 I- -> 3 I3- + 3 H2O. The rate of this reaction depends on the temperature, and on the concentrations of iodate, iodide, and hydrogen ions.