Chromite ore has the formula:
(a)- FeCr2O6

(b)- FeCr2O4

(c)- FeCr2O7

(d)- Both A and B

The correct answer is:

(b) FeCr₂O₄

Here's the explanation:

Chromite ore is an important source of chromium. Its chemical formula is FeCr₂O₄. This compound consists of iron (Fe), chromium (Cr), and oxygen (O) in a specific ratio:

Fe: Iron
Cr₂: Two atoms of chromium
O₄: Four atoms of oxygen
The formula FeCr₂O₄ indicates that for every iron atom, there are two chromium atoms and four oxygen atoms.

Let's break down why the other options are not correct:

FeCr₂O₆: This would imply a different oxidation state and formula that doesn't correspond to chromite ore.
FeCr₂O₇: This formula corresponds to a different compound, such as a chromium oxide, but not chromite ore.
Both A and B: Since only FeCr₂O₄ is the correct formula for chromite ore, this option is incorrect.
So, FeCr₂O₄ is the correct representation of chromite ore.