Question

Obtain small pieces of zinc (zn), copper (cu), and magnesium (mg). Observe and record the appearance of each. Place 3 ml of 1 M HCl(aq) in each of three test tubes. Carefully add a different metal to each of the HCl test tubes. Observe and record any sign of a reaction for each metal. Remember to carefully feel the temperature of each test tube. What are the observations and reactions when zinc, copper, and magnesium are added to 1 M HCl(aq)?

Answer 1

Zinc and magnesium react with hydrochloric acid, releasing hydrogen gas and forming their respective chloride salts, with magnesium reacting more vigorously. Copper does not react noticeably as it is less reactive than hydrogen. The exothermic reactions can increase the temperature of the test tubes.

Step-by-step explanation:

When different metals are added to 1 M hydrochloric acid (HCl), the observations vary based on their reactivity. Here are the expected observations and reactions for zinc (Zn), copper (Cu), and magnesium (Mg) when each is added to HCl:

• Zinc: Solid zinc reacts with aqueous hydrochloric acid to release hydrogen gas and form zinc chloride (ZnCl₂) in solution. The reaction can be observed as bubbling due to the hydrogen gas, and there may be an increase in temperature due to the exothermic reaction. The balanced chemical equation is:
  Zn(s) + 2HCl(aq) → ZnCl₂(aq) + H₂(g).
  
  
• Copper: Copper does not react with dilute hydrochloric acid because it is less reactive than hydrogen. Therefore, no noticeable reaction will be observed when copper is placed in HCl.
  
  
• Magnesium: Magnesium reacts more vigorously with HCl than zinc does. It produces hydrogen gas and forms magnesium chloride (MgCl₂) in solution. The reaction will produce more intense bubbling and possibly a greater temperature increase compared to zinc due to the higher reactivity of magnesium. The balanced chemical equation is:
  Mg(s) + 2HCl(aq) → MgCl₂(aq) + H₂(g).