Theory:

Let us see how bases react 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 bases react with metals.

Apparatus required:
  • Test tube
  • Delivery tube
  • Glass tub
  • Candle
  • Zinc granules
  • Water
  • Soap
  • Sodium hydroxide \(NaOH\)
Step 1: Take a test tube and add \(2mL\) of sodium hydroxide (NaOH\) solution and add a few pinches of zinc granules.
 
Step 2: Heat the test tube for few minutes until it is warm.
 
Step 3:
  • 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 4: The other end of the delivery tube should be placed inside the glass tube filled with a soap solution.
 
fina naoh.png
Bases on reaction with metals
 
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:
  • \(Sodium hydroxide + Zinc\rightarrow Salt + Hydrogen gas\)
  • Therefore, the chemical reaction can be written as  \(2NaOH + Zn\rightarrow Na_2ZnO_2+ H_2\)
Here the formed salt is sodium zincate with the chemical formula \(Na_2ZnO_2\).
Therefore, the overall reaction can be written as
 
\(Base+ Metal \rightarrow Salt + Hydrogen gas\)
We know that a chemical reaction occurs between metal and a base. But, it is not possible with all metals as most of the metals have the same characteristics as that of a base.
Note: If the cation of the base is less reactive than the metal, the reaction is possible.