The reaction 2HGOS(S) - 2Hg(1)+02(g), you produce 1 mole of HG. What is your percent yield ? you expected to produce 2mol of HG.
100%
50%
30%
20%

Option 2. 50 %

Explanation:

Reaction: 2HgO (s) →  2Hg (l) +  O₂(g)

Ratio is 2:2, 2 moles of mercury oxide produce 2 moles of liquid mercury.

If you produced 1 mol of Hg, then the percent yield reaction is 50%

Percent yield is:

[Produced yield (what you produced) / Theoretical yield (what you excpected to be produced)] . 100 → (1 mol of Hg / 2 mol of Hg) .100 = 50%