A synthesis reaction is a type of chemical reaction in which two or more simple substances combine to form a more complex product. The general form of a synthesis reaction is:
[tex]\[ A + B \rightarrow AB \][/tex]
Now let's analyze each given reaction:
1. [tex]\[ 2 HgO \rightarrow 2 Hg + O_2 \][/tex]
- This reaction shows the decomposition of mercury(II) oxide (HgO) into mercury (Hg) and oxygen (O₂).
- This is a decomposition reaction, not a synthesis reaction.
2. [tex]\[ AgNO_3 + NaCl \rightarrow AgCl + NaNO_3 \][/tex]
- This reaction shows silver nitrate (AgNO₃) reacting with sodium chloride (NaCl) to form silver chloride (AgCl) and sodium nitrate (NaNO₃).
- This is a double displacement reaction, not a synthesis reaction.
3. [tex]\[ HCl + NaHCO_3 \rightarrow H_2O + CO_2 + NaCl \][/tex]
- This reaction shows hydrochloric acid (HCl) reacting with sodium bicarbonate (NaHCO₃) to form water (H₂O), carbon dioxide (CO₂), and sodium chloride (NaCl).
- This is an acid-base reaction that involves decomposition, not a synthesis reaction.
4. [tex]\[ 2 Na + Cl_2 \rightarrow 2 NaCl \][/tex]
- This reaction shows sodium (Na) reacting with chlorine (Cl₂) to form sodium chloride (NaCl).
- This reaction involves the combination of two elements, sodium and chlorine, to form a more complex compound, sodium chloride.
- This is the correct example of a synthesis reaction.
Therefore, the best description of a synthesis reaction among the given choices is:
[tex]\[ 2 Na + Cl_2 \rightarrow 2 NaCl \][/tex]
