Question

Write a balanced chemical equation for the decomposition of solid sodium sulfide in aqueous solution. A) Na2S(s) → Na+(aq) + S(s) B) NaS2(s) → Na+(aq) + 2S2-(aq) C) Na2S(aq) → 2Na+(s) + S2-(s) D) Na2S(s) → 2Na+(aq) + S2-(aq)

Answer 1

The answer is D) Na2S(s) → 2Na+(aq) + S2-(aq)

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Answer 2

Sodium sulfide formula is Na₂S.
Na is a group 1 element, it has one valence electron therefore it is ready to give that valence electron and form an ionic bond. Once it gives out the electron it becomes a positive ion - Na⁺
sulfur is a group 6 element, has 6 electrons its outer shell and needs to gain 2 more electrons to become stable. Once it gains 2 electrons it becomes a negative ion - S²⁻.
Since Na only gives out 1 electron, S²⁻ ion needs to take in 2 electrons, therefore forms an ionic compound with 2 Na⁺ ions.
decomposition of Na₂S is as follows;
Na₂S(s) --> 2Na⁺(aq) + S²⁻ (aq)