Question

Which of the following statement(s) is/are true/false?

Statements:

A. The following is an example of a reversible reaction

N2(g) + 3H2(g) \(\rightleftharpoons\)  2NH3(g)

B. An example of the following photodecomposition reaction

CaCO3(s) \(\xrightarrow{heat}\)  CaO(s) + CO2(g)

1. Both A and B are true
2. Both A and B are false
3. Only B is true
4. Only A is true

Answer 1

Correct Answer - Option 4 : Only A is true

The correct answer is Only A is true.

 

• Irreversible chemical reactions can occur in only one direction.
  • The reactants can change to the products, but the products cannot change back to the reactants.
• Reversible chemical reactions can occur in both directions.
  • The reactants can change to the products, and the products can also change back to the reactants.​​
  • Example
    • N2(g) + 3H2(g) \(\rightleftharpoons\)  2NH3(g)
    • Hence statement A is true.
• ​CaCO3(s) \(\xrightarrow{heat}\)  CaO(s) + CO2(g)
  • It is a decomposition reaction as Calcium carbonate undergoes decomposition and the carbon dioxide gas formed.
    • The second product of the reaction, the calcium oxide.
    • The chemical reaction in which two or more products are formed from a single reactant is called the ''Decomposition reaction”.
  • Hence statement B is not true.

 

• A combination reaction is a reaction where two or more elements or compounds combine to form a single compound. Such reactions are represented by equations of the following form: X + Y → XY.
• The combination of two or more elements to form one compound is called a combination reaction.
• Other types of Chemical Reactions:
  • Decomposition reaction: The opposite of a combination reaction, a complex molecule breaks down to make simpler ones.
    •  AB → A + B.
  • Precipitation reaction: Two solutions of soluble salts are mixed resulting in an insoluble solid (precipitate) forming.
    • A + Soluble salt B  → Precipitate + soluble salt C.
  • Neutralization reaction: An acid and a base react with each other. Generally, the product of this reaction is salt and water.
    • Acid + Base → Salt + Water.
  • Combustion reaction: Oxygen combines with a compound to form carbon dioxide and water. These reactions are exothermic, meaning they give off heat. 
    • A + O2 → H2O + CO2.
  • Displacement reaction: One element takes place with another element in the compound. 
    • A + BC → AC + B.