In acidic medium $As X_{2} S X_{3}$ is oxidised by nitrate: $As X_{2} S X_{3} + NO X_{3} X^{-} + H X_{2} O AsO X_{4} X^{3 -} + SO X_{4} X^{2 -} + NO + H X^{+}$ . Find the sum of all coefficients in the balanced equation written with the smallest whole numbers. Give the answer as an integer.

Numerical answer type, tolerance 0.1.

Answer: 86

Per

As X_{2} S X_{3}

: 2 As go +3 to +5 (4 electrons) and 3 S go -2 to +6 (24 electrons), total 28 electrons. N gains 3, so

As X_{2} S X_{3}

NO X_{3} X^{-}

= 3 : 28. Charge and atom balance give

3 As X_{2} S X_{3} + 28 NO X_{3} X^{-} + 4 H X_{2} O 6 AsO X_{4} X^{3 -} + 9 SO X_{4} X^{2 -} + 28 NO + 8 H X^{+}

. The coefficients add up to 86.