The moles of KClO₃ that were consumed is 0.343 moles
calculation
2KClO₃ → 2KCl +3O₂
step 1: find the moles KCl
moles = mass÷ molar mass
25.6 g÷74.55 g/mol =0.343 moles
Step 2 : use the mole ratio to determine the moles KClO₃
from equation above KClO₃ : KCl is 2:2 =1:1
therefore the moles KClO₃ = 0.343 moles