The equation 4HNO3 + ZnO -> 2NO2 + 2H2O + Zn(NO3)2

Detailed information about the equation 4HNO₃ + ZnO -> 2NO₂ + 2H₂O + Zn(NO₃)₂
The above chemical equation describes a chemical reaction between nitric acid (HNO₃) and zinc oxide (ZnO) to produce nitrogen dioxide (NO₂), water (H₂O), and zinc nitrate (Zn(NO₃)₂).

Reaction conditions
The above reaction typically occurs under normal temperature and pressure conditions. HNO₃ needs to be in liquid form and ZnO in solid form for the reaction to take place effectively.

Reaction process
The reaction begins when HNO₃ and ZnO come into contact with each other. HNO₃, a strong acid, reacts with ZnO, a base, to create water and zinc nitrate. During this process, two hydrogen atoms from HNO₃ combine with one oxygen atom from ZnO to produce water. Simultaneously, two nitrogen atoms and five oxygen atoms from HNO₃ combine with one zinc atom from ZnO to produce zinc nitrate. Lastly, the remaining two nitrogen atoms from HNO₃ combine with the remaining oxygen atom from ZnO to form nitrogen dioxide.

Phenomena that occur
When the reaction occurs, you will see a reddish-brown smoke due to the creation of nitrogen dioxide. At the same time, oxygen atoms are eliminated and form water. The creation of zinc nitrate also contributes to the final solution’s color.