Determine the oxidation number of Sulfur atom in Ca(HSO4)2

The oxidation number of Sulfur in Ca(HSO4)2 is +6.

Step 1: In the compound Ca(HSO4)2, the oxidation number of Ca is +2.

Step 2: The oxidation number of Hydrogen in HSO4- is +1 and the oxidation number of Oxygen is -2.

Step 3: The overall charge of the HSO4- ion is -1. Therefore, the oxidation number of Sulfur (S) must be +6 to balance the charges.

Therefore, the oxidation number of Sulfur in Ca(HSO4)2 is +6.