Why can't `NH_4NO_2` be used for `N_2` preparation?

Why HNO_3 Can’t be use for the preparation of H_2O_2 by BaO_2 ? What is Marshall acid?

Which out of dil. H_2SO_4 , HCl and HNO_3 can be used in the preparation of carbon dioxide from PbCO_3 ?

Why does NO_2 dimerise to form N_2O_4 ?

Why paste of BaO_(2) is used in laboratory preparation of H_(2) O_(2) ?

Why is dilute H_2SO_4 not used in the Laboratory preparation of CO_2 ?

Explain why in the laboratory preparation of H_(2)O_(2) : Mn O_(2) " "or PbO_(2) cannot be used instead of Ba O_(2) for preparing H_(2)O_(2) - why ?

Why NO_2 shows tendency to form N_2O_4 ?

Why blast furnace is not used in the extraction of zinc? Why Iron can't be extracted form iron pyrities?

Why is conc. H_(2)SO_(4) used to prepare more voltaile acids form their corresponding salts ?

Why can aryl halides not be prepared by reaction of phenol with HCl in the presence of ZnCl_(2) ?