What happens when few pieces of zinc is added into a test tube containing dilut hydrochloric acid?

3 answers

When a few pieces of zinc are added into a test tube containing dilute hydrochloric acid, a chemical reaction occurs. The zinc reacts with the hydrochloric acid to produce zinc chloride (ZnCl2) and hydrogen gas (H2). This is represented by the following equation:

Zn + 2HCl → ZnCl2 + H2

The hydrogen gas is released as bubbles, while the zinc chloride dissolves in the acid solution. The reaction is typically exothermic, meaning it produces heat.
Place a few pieces of zinc into some dilute nitric acid in a test tube. Does a reaction occur like that with hydrochloric acid? Explain.
When a few pieces of zinc are added into dilute nitric acid, a reaction occurs, but it is different from the reaction with hydrochloric acid. Nitric acid is a stronger oxidizing agent compared to hydrochloric acid. When zinc reacts with nitric acid, it undergoes a redox reaction.

The reaction can be represented by the following equation:

Zn + 2HNO3 → Zn(NO3)2 + H2O + NO2

In this reaction, zinc displaces hydrogen from nitric acid, resulting in the formation of zinc nitrate (Zn(NO3)2), water (H2O), and nitrogen dioxide (NO2). The nitrogen dioxide gas is reddish-brown in color and can be observed as a gas bubbling out of the reaction mixture.

It is important to note that nitric acid is a corrosive and strong oxidizing agent, so handling it should be done with caution.