Most metal oxide are thermally stable at temperature upto `1000^(@)C` but the oxide of metals below hydrogen in the electrochemical series fairly. Thus `HgO and Ag_(2)O` decomposes on heating.
Q. Correct code for following thermal decomposition reaction(s) evolving gas having equal number of `sigma- and pi-`bonds is :
(i)`BeCO_(3)overset(delta)(to)` (ii)`ZnSO_(4)overset(delta)underset(gammalt800^(@)C)(to)`
(iii)`FeSO_(4)overset(300^(@)C)(to)` (iv)`(NH_(4))_(2)Cr_(2)O_(7)overset(delta)(to)`

Options

A. i, ii
B. i, iii, iv
C. i, ii, iii and IV
D. All of these

Answer

C