Introduction:
In this question, we are given that x moles of K2Cr2O7 oxidizes 1 mole of ferrous oxalate in acidic medium. We need to determine the value of x from the given options (a. 3, b. 1.5, c. 0.5, d. 1.0). To solve this, we will use the concept of stoichiometry and balanced chemical equations.

Stoichiometry:
Stoichiometry is the calculation of reactants and products in chemical reactions based on the balanced chemical equation. It allows us to determine the quantitative relationships between substances in a chemical reaction.

Balanced Chemical Equation:
The balanced chemical equation for the reaction between K2Cr2O7 and ferrous oxalate in acidic medium can be represented as follows:

K2Cr2O7 + 6FeC2O4 + 14H2SO4 → 2K3[Cr(SO4)2(H2O)4] + 12CO2 + 6FeSO4 + 7H2O

From the equation, we can see that 1 mole of K2Cr2O7 reacts with 6 moles of FeC2O4.

Applying Stoichiometry:
To determine the value of x, we need to find the moles of K2Cr2O7 required to oxidize 1 mole of FeC2O4. As per the balanced equation, the ratio is 1:6. Therefore, x = 6.

Answer:
The value of x, which represents the moles of K2Cr2O7 that oxidizes 1 mole of ferrous oxalate, is 6. Therefore, none of the given options (a. 3, b. 1.5, c. 0.5, d. 1.0) is correct.

Conclusion:
Using stoichiometry and the balanced chemical equation, we have determined that x = 6 moles of K2Cr2O7 are required to oxidize 1 mole of ferrous oxalate in acidic medium.