Question

Which of the following is a main characteristic of chemical reaction?

• A. Formation of precipitate
• B. Colour change
• C. Evolution of gas
• D. All of these

Answer 1

The correct option is D All of these

The characteristics of chemical reactions are :
1) Change of colour - When citric acid is added to Potassium permanganate then the purple colour starts discharging.
2)Change of state - When hydrogen(gas) reacts with oxygen(gas), they form water a liquid.
3)Evolution of a gas - When lead nitrate is heated it decomposes to lead oxide, nitrogen dioxide with oxygen.
4) Formation of a precipitate - When lead nitrate reacts with potassium iodide, it forms a yellow precipitate of Lead iodide and potassium nitrate.