MCQ
$(NH_4 )_2Cr _2O_7$ on heating liberates a gas. The same gas will be obtained by
- ✓Heating $NH_4NO_2$
- BHeating $NH_4NO_3$
- CHeating $(NH_4)_2SO_4$
- DTreating $Mg_3N_2$ with $H _2O$
$NH_4NO_2 \to N_2 + H_2O$
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Assertion : For hydrogenation reactions, the catalytic activity increases from Group $5$ to Group $11$ metals with maximum activity shown by Group $7-9$ elements.
Reason : The reactants are most strongly adsorbed on group $7-9 $ elements.
Compare rate of $E_2$ reaction
Statement $(I)$: A solution of $\left[\mathrm{Ni}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+}$ is green in colour.
Statement $(II)$: A solution of $\left[\mathrm{Ni}(\mathrm{CN})_4\right]^{2-}$ is colourless.
In the light of the above statements, choose the most appropriate answer from the options given below:
