In ZnHSO32, the oxidation number of Zn can be determined as follows:

Let x be the oxidation number of Zn:

1(x) + 1(-2 + 1 + 3(-2)) = 0.

Solving for x gives:

x = (+2 - 1 - 6) = -5.

Therefore, the oxidation number of Zn in ZnHSO32 is -5.