AsO₄³⁻ + 11H⁺ + 8e⁻ ----> AsH₃ + 4H₂O
Zn ---> Zn²⁺ + 2e⁻ / * 4
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AsO₄³⁻ + 11H⁺ + 8e⁻ ----> AsH₃ + 4H₂O
4Zn ---> 4Zn²⁺ + 8e⁻
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AsO₄³⁻ + 4Zn + 11H⁺ ----> AsH₃ + 4Zn²⁺ + 4H₂O