Question

Which of the following does not give oxygen on heating?

• A. $K_{2}C{r}_2{O}_7$
• B. $(N{H}_4{)}_{2}C{r}_2{O}_7$
• C. $KCl{O}_3$
• D. $Zn(Cl{O}_3{)}_2$

Answer 1

The correct option is B $(N{H}_4{)}_{2}C{r}_2{O}_7$

$2KCl{O}_3\to 2KCl+3O_2\uparrow$
$2Zn(Cl{O}_3{)}_2\to ZnC{l}_2+3O_2\uparrow$
$K_{2}C{r}_2{O}_7\to 4K_{2}Cr{O}_4+2C{r}_2{O}_3+3O_2\uparrow$
$\left(N{H}_4\right)C{r}_2{O}_7\to C{r}_2{O}_3+4H_{2}O+N_2\uparrow$
All the given compounds are oxygen-rich. All of them, except ammomium dichromate $\left[\right(N{H}_4{)}_{2}C{r}_2{O}_7]$, give oxygen on heating. On the other hand, Ammonium dichromate gives nitrogen on heating.