NO2 (aq) + Al(s) —> NH3(aq) + Al(OH)4 (aq)

A.

They are like other investigations? say there was a murder u have to do blood test and finger prints which run through a lab. 

Rn in the right answer

Answerδh > 0explanationc₆h₆  (s)  → c₆h₆ (l)if you are changing it from a solid to a liquid, you are pretty much melting the solid. this requires heat energy. therefore, the reaction is endothermic (takes in energy); the system enthalpy increases as the reaction proceeds: δh > 0.