To determine which of the given equations is correctly balanced, we need to check that the number of atoms of each element on the reactant side (left side) is equal to the number of atoms of the same element on the product side (right side).
Option A:
[tex]\[ \ce{NaClO3 -> NaCl + 3 O2} \][/tex]
Let's break it down:
- Reactants: 1 Na, 1 Cl, 3 O
- Products: 1 Na, 1 Cl, 6 O (since [tex]\(3 \times \ce{O2} = 3 \times 2 = 6\)[/tex])
Not balanced, as Oxygen atoms are 3 on the left and 6 on the right.
Option B:
[tex]\[ \ce{2 HgO -> 2 Hg + O2} \][/tex]
Breaking it down:
- Reactants: 2 Hg, 2 O
- Products: 2 Hg, 2 O (since [tex]\( \ce{O2} = 2\)[/tex])
Balanced, as the number of atoms for each element is the same on both sides.
Option C:
[tex]\[ \ce{2 ZnS + O2 -> 2 ZnO + 2 SO2} \][/tex]
Breaking it down:
- Reactants: 2 Zn, 2 S, 2 O (since [tex]\( \ce{O2} = 2\)[/tex])
- Products: 2 Zn, 2 S, 6 O (since [tex]\( \ce{2 ZnO} = 2(1+1) = 2 + 2 = 4 \)[/tex] and [tex]\( \ce{2 SO2} = 2 \times 2 = 4\)[/tex])
Not balanced, as Oxygen atoms are 2 on the left and 6 on the right.
Option D:
[tex]\[ \ce{4 CO + Fe3O4 -> 4 CO2 + Fe} \][/tex]
Breaking it down:
- Reactants: 4 C, 4 O, 3 Fe
- Products: 4 C, 8 O (since [tex]\( \ce{4 CO2} = 4 \times 2 = 8\)[/tex]), Fe (single)
Not balanced, as Oxygen atoms are 4 on the left and 8 on the right; and Iron atoms are 3 on the left and 1 on the right.
Option E:
[tex]\[ \ce{2 Fe + 2 Cl2 -> 2 FeCl3} \][/tex]
Breaking it down:
- Reactants: 2 Fe, 4 Cl (since [tex]\( \ce{2 Cl2} = 2 \times 2 = 4\)[/tex])
- Products: 2 Fe, 6 Cl (since [tex]\( \ce{2 FeCl3 = 2 \times 3 = 6\)[/tex])
Not balanced, as Chlorine atoms are 4 on the left and 6 on the right.
Thus, the correctly balanced equation is:
[tex]\[ \boxed{B. \ce{2 HgO -> 2 Hg + O2}} \][/tex]
