Theory:

Let us see how acid reacts with metal with the help of some activities:
Important!
Caution: The experiment should be performed in the presence of a teacher.
Example:
Activity 1: The experiment aims to see how do acids react with metals.

Apparatus required:
  • Test tube
  • Delivery tube
  • Glass tub
  • Candle
  • Zinc granules
  • Water
  • Soap
  • Dilute \(H_2SO_4\)
Step 1: Take a test tube and add \(5mL\) of dilute sulphuric acid \(H_2SO_4\) and add a few pinches of zinc granules.
 
Step 2:
  • Observe the test tube for any changes.
  • Fit the test tube mouth with a cork.
  • Attach one end of the delivery tube to it.
Step 3: The other end of the delivery tube should be placed inside the glass tube filled with a soap solution.
 
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Acids on reaction with metal
 
Observation: The liberation of gas from the reaction passes through the soap tub forming bubbles.
  
Result: Since the hydrogen gas does not dissolve in a soap solution, it forms hydrogen gas bubbles.
To prove that the formed gas is hydrogen, we can do a small test using a candle.
 
Take a burning candle near a gas-filled bubble that is formed from the above reaction. We can find the burning of hydrogen gas with a pop sound and turns the candle off.
 
Final observation:
  • A colourless and odourless gas is formed.
  • The formed gas does not dissolve in a soap solution, as a result bubbles are formed.
  • The liberated gas found to be as hydrogen, which produces a pop sound and turns off the candle.
Conclusion:
 
\(dil.Sulphuric acid + Zinc granules \rightarrow Salt + Hydrogen gas\)
 
Therefore, the chemical reaction can be written as
 
\(H_2SO_4 + Zn\rightarrow ZnSO_4 + H_2\)
Example:
Let us now see the reaction of the other acids with zinc granules.
  • \(Zn + 2{HCl}\rightarrow ZnCl_2 + H_2\)
  • \(Zn + 2 HNO_3\rightarrow  Zn(NO_3)_2 + H_2\)
  • \(Zn + 2CH_3​COOH\rightarrow  Zn(CH_3​COO)_2​ + H_2​\)
Note: When we repeat the activity with other acids such as hydrochloric acid \(HCl\), nitric acid \(HNO_3\) and acetic acid \(CH_3COOH\), the same results will be produced where the formation of salts varies according to the acid.
Therefore, the overall reaction can be written as
\(Acid + Metal \rightarrow Salt + Hydrogen gas\)
It does not matter which acid or metal is used for the reaction, we always get salt along with the hydrogen gas.
 
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Reactivity series
 
However, the rate of the reaction is determined by the metal used and its position in the reactivity series. The more reactive a metal is, the faster it reacts with acids.