Question
Question: 10<sup>–2</sup> moles of Fe<sub>3</sub>O<sub>4</sub> is treated with excess of KI solution in presen...
10–2 moles of Fe3O4 is treated with excess of KI solution in presence of dilute H2SO4 , the products are Fe2+ and I2 (g). What volume of 0.1 (M) Na2S2O3 will be needed to reduce the liberated I2 (g) ?
A
50 ml
B
100 ml
C
200 ml
D
400 ml
Answer
200 ml
Explanation
Solution
\ Fe3O4 + 2I– ® Fe2+ + I2
\ no. of moles of I2 produced = 10–2 moles
Let v ml 0.1 (M) Na2S2O3 solution is required
\ v × 10–4 = 2 × 10–2
or v = 200 ml.