Transition and InnerTransition Elements - Result Question 29

30. $\left(NH _4\right) _2 Cr _2 O _7$ on heating gives a gas which is also given by

$(2004,1 M)$

(a) heating $NH _4 NO _2$

(b) heating $NH _4 NO _3$

(c) $Mg _3 N _2+H _2 O$

(d) $Na$ (comp.) $+H _2 O _2$

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Solution:

Ammonium dichromate on heating produces $N _2(g)$. $NH _4 NO _2$

also gives $N _2$ on heating :

$ \begin{gathered} \left(NH _4\right) _2 Cr _2 O _7 \stackrel{\Delta}{\longrightarrow} N _2+Cr _2 O _3+4 H _2 O \\ NH _4 NO _2 \stackrel{\Delta}{\longrightarrow} N _2+2 H _2 O \end{gathered} $