Question

Which of the following is not a sign that a chemical reaction has occurred? a) Change in temperature b) Change in shape c) Change in colour d) Forma9on of a gas

Answer 1

b) change in shape is not the sign of chemical reaction

Answer 2

The option which is not a sign of a chemical reaction's occurrence is (b) Change in Shape

Explanation:  

• A chemical reaction is the transformation of one chemical substance into another chemical substance which leads to alteration in molecules chemically. It changes a substance's chemical composition.During a chemical reaction, the following changes can occur:

      ⇒ Change in temperature: When Calcium oxide reacts with water  

      ⇒ Change in color: Displacement of copper by iron in copper    sulphate solution.  

      ⇒ Formation of gas: Photosynthesis  

      ⇒ But, change in shape is a physical reaction which just changes the structure of molecules physically. For example: molding of clay.  

Hence, the option which is not a sign of a chemical reaction's occurrence is (b) Change in Shape