Which of the following does not give oxygen on heating ?

Options

A. `K_2 Cr_2 O_7`
B. `(NH_4)_2 Cr_2 O_7`
C. `KClO_3`
D. `Zn(ClO_3)_2`

Answer

B

Explanation

`(NH_(4))_(2) Cr_(2) O_(7)` on heating gives `N_(2(g))`.
`(NH_(4))_(2) Cr_(2) O_(7) overset(Delta) rarr N_(2) + Cr_(2) O_(3) + 4 H_(2) O`
whereas compounds is `(a), (c)` and `(d)` all gives oxygen on heating.
(a) `4K_(2) Cr_(2) O_(7) overset(Delta) rarr 4K_(2) CrO_(4) + 2 Cr_(2) O_(3) + 3O_(2)`
When `K_(2) Cr_(2) O_(7)` is heated it decomposes with the evolution of `O_(2)`.
(c) `underset("Potassium chlorate") (2 KClO_(3)) overset (Delta) rarr 2 KCl + 3 O_(2) (g)`
(d) `underset("Zinc chlorate") (Zn(ClO_(3))_(2)) overset (Delta) rarr ZnCl_(2) + 3O_(2) (g)`.