The reaction you're describing involves silver sulfide (Ag₂S) and sodium cyanide (NaCN) in the presence of water (H₂O). This is typically a situation where Ag₂S is being treated with NaCN, often to extract silver from the sulfide ore.

The likely reaction that occurs here is the complexation of silver ions (from Ag₂S) with cyanide ions (from NaCN), forming a soluble complex. Here is a simplified representation of the reaction:

1. Silver sulfide (Ag₂S) reacts with sodium cyanide (NaCN) in the presence of water:

\[
\text{Ag}_2\text{S} + 4 \text{NaCN} + 2 \text{H}_2\text{O} \rightarrow 2 \text{Na}_2\text{[Ag(CN)}_2\text{]} + \text{H}_2\text{S}
\]

In this reaction:
- Silver ions (Ag⁺) are extracted from Ag₂S and form a soluble silver cyanide complex \( \text{[Ag(CN)}_2\text{]}^{-} \).
- Hydrogen sulfide (H₂S) is a byproduct.

Note that the presence of water here does not significantly change the stoichiometry of the solid reagents and products, as they are typically in a solution phase for the reaction to proceed effectively.