Chemical Reactions and Equations

When carbon dioxide is passed through lime water, it turns milky, why?

What do you understand by precipitation reaction? Explain with suitable examples.

What is a balanced chemical equation?

You are given the following materials

(i) Marble chips (ii) dilute hydrochloric acid (iii) Zinc granules

Identify the type of reaction when marble chips and zinc granules are added separately to acid taken in two test tubes.

If you collect silver coins and copper coins you may have seen that after some days a black coating forms on silver coins and a green coating on copper coins. Which chemical phenomenon is responsible for these coatings? Write the chemical name of the black and green coatings.