The oxidation state of an element refers to the number of electrons it loses, gains, or shares when it forms a compound. In the given compound, K2Cr2O7, the total oxidation state of potassium (K) is +2 (since there are two K atoms and each contributes +1), and the total oxidation state of oxygen (O) is -2 (since there are seven O atoms and each contributes -2). The compound is neutral, which means the sum of all the oxidation states must be zero. Therefore, we can use this information to find the oxidation state of chromium (Cr). Let x be the oxidation state of Cr. Then, (+2) + 2x + (-2)(7) = 0 Simplifying: 2x - 12 = 0 2x = 12 x = 6 Therefore, the oxidation state of Cr in K2Cr2O7 is +6. So the correct option is +6.