Question

How many moles of iodine are liberated when 1 mole of potassium dichromate reacts with potassium iodide?

• A. 1
• B. 2
• C. 3
• D. 4

Answer 1

The correct option is C

3

$K_{2}C{r}_2{O}_7+4H_{2}S{O}_4\to K_{2}S{O}_4+C{r}_2(S{O}_4{)}_3+4H_{2}O+3\left[O\right]$

$[2KI+H_{2}S{O}_4+\left[O\right]\to K_{2}S{O}_4+I_2+H_{2}O]\times 3$

$K_{2}C{r}_{2}O7+7H_{2}S{O}_4+6KI\to 4K_{2}S{O}_4+3I_2+C{r}_2(S{O}_4{)}_3+7H_{2}O$