### This is an oxidation-reduction (redox) reaction:

*2 NaI + 2 e- → 2 Na0 (reduction)*

*2 NaI + 2 e- → 2 Na0 (reduction)*

*S-II - 2 e- → S0 (oxidation)*

*S-II - 2 e- → S0 (oxidation)*

**Na2S **is an oxidizing agent, **Na2S **is a reducing agent.

### Word equation

*sodium sulfide → sodium + mixed sulfur*

### Input interpretation

*Na2S → 2 Na + S*

**Sodium sulfide sodium mixed sulfur**

### Balanced equation

Balance the chemical equation algebraically:

*Na2S → 2 Na + S*

Add stoichiometric coefficients, c, to the reactants and products:

*c1 Na2S → c2 2Na + c3 S*

Set the number of atoms in the reactants equal to the number of atoms in the products for **Na **and **S:**

*Na: 2c1 = c2*

*S: c1=c3*

Since the coefficients are relative quantities and underdetermined, choose a coefficient to set arbitrarily. To keep the coefficients small, the arbitrary value is ordinarily one. For instance, set ** c1 = 1** and solve the system of equations for the remaining coefficients:

*C1 = 1 C2=2 *

*C3 = 1*

Substitute the coefficients into the chemical reaction to obtain the balanced

equation:

Answer:

*Na2S → 2 Na + S*