Complete the following :
(i) `CH_(3)COONaoverset(NaOH)underset(CaO"/"Heat)rarr`

Explanation

To complete the reaction given in the question, we will follow the process of decarboxylation of the sodium salt of acetic acid (sodium acetate) in the presence of soda lime (a mixture of NaOH and CaO) and heat.

### Step-by-Step Solution:

1. **Identify the Reactants**:
The reactant given is sodium acetate, which is represented as \( CH_3COONa \).

2. **Understanding Soda Lime**:
Soda lime is a mixture of sodium hydroxide (NaOH) and calcium oxide (CaO) in a ratio of 3:1. This mixture is used for decarboxylation reactions.

3. **Decarboxylation Reaction**:
When sodium acetate is heated with soda lime, a decarboxylation reaction occurs. In this reaction, the carboxyl group (-COOH) is removed from the sodium acetate, resulting in the formation of an alkene.

4. **Formation of Products**:
The main product of this reaction is ethylene (ethene, \( C_2H_4 \)), and sodium carbonate (\( Na_2CO_3 \)) is produced as a by-product. The balanced equation for the reaction can be written as:
\[ CH_3COONa + NaOH \xrightarrow{CaO, \text{Heat}} C_2H_4 + Na_2CO_3 \]

5. **Final Equation**:
Therefore, the complete reaction can be summarized as:
\[ CH_3COONa \overset{NaOH, CaO, \text{Heat}}{\longrightarrow} C_2H_4 + Na_2CO_3 \]

### Final Answer:
\[ CH_3COONa \overset{NaOH, CaO, \text{Heat}}{\longrightarrow} C_2H_4 + Na_2CO_3 \]