Question

(a) What happens when zinc granules are heated with sodium hydroxide solution? Write an equation of the reaction which takes place.
(b) What happens when bases react with non-metal oxides? Explain with the help of an example. What does this reaction tell us about the nature of non-metal oxides?

Answer 1

Hint: When a base reacts with a metal, the products of the reaction are salt and hydrogen gas is released. Zinc is a metal which is reactive in nature and Sodium hydroxide, which has a chemical formula NaOH, is a strong base. We should remember that all the metals do not react with bases to form salts but only the reactive metals react with bases.

Complete answer:
(a) We now know that, when a reaction takes place between a reactive metal and a base, it produces a salt and hydrogen is released. So, in the above given reaction, Zinc is a metal which is reactive in nature and Sodium hydroxide, which has a chemical formula NaOH, is a strong base. When they react with each other Sodium zincate salt is formed and hydrogen gas is released.
The reaction of zinc granules with sodium hydroxide is given by:
 $ Zn\left( s \right)\; + \;NaOH\left( {aq} \right)\; \to N{a_2}Zn{O_2}\;\left( {aq} \right)\; + \;{H_2}\left( g \right)\; $
The product formed is a salt called Sodium Zincate $ (N{a_2}Zn{O_2}) $ and hydrogen gas is released.
(b) When bases react with non-metal oxides, then they form salt and water.
For Example: When Calcium hydroxide reacts with carbon dioxide, the products are calcium carbonate and water. The reaction is given as:
 $ Ca{(OH)_2}(aq) + C{O_2}(g) \to CaC{O_3}(s) + {H_2}O(l) $
This reaction tells that non-metal oxides are acidic in nature because by reacting with bases they are forming salt and water.

Note:
We should remember that base reacts with acids to give a salt which can be acidic, basic or neutral according to the type of acids and bases taken. Strong acids and strong bases give neutral salts. Strong acids and weak bases give acidic salt while strong bases and weak acids give the basic salts.