In the reaction of potassium dichromate, potassium chloride and sulfuric acid (conc.), the oxidation state of the chromium in the product is +

In conc. sulfuric acid and potassium chloride, potassium dichromate produces chromyl chloride, $$CrO_2Cl_2$$, which is a neutral molecule containing chromium.

Rule: In any neutral molecule, the sum of oxidation states equals zero. Let the oxidation state of chromium in $$CrO_2Cl_2$$ be $$x$$. Then
$$x + 2\times(\text{ox. state of O}) + 2\times(\text{ox. state of Cl}) = 0\quad-(1)$$

We know: Oxygen has oxidation state $$-2$$ and chlorine has oxidation state $$-1$$. Substituting these into $$(1)$$ gives:
$$x + 2(-2) + 2(-1) = 0\quad-(2)$$

Simplify equation $$(2)$$:
$$x -4 -2 = 0$$
$$x -6 = 0\quad-(3)$$

From $$(3)$$, we get:
$$x = 6$$

Therefore, the oxidation state of chromium in the product $$CrO_2Cl_2$$ is +6.