Can oxidation or reduction take place alone? Why or why not? What are such reactions called?

What happens when zinc granules are treated with dilute solutions of $H_{2}SO_{4}$,$HCl$,and $HNO_{3}$? Also,write the chemical equations if a reaction occurs.

State whether the following statement is true or false:
Calcium oxide is also called lime or quicklime.

Which one of the following is a chemical change? Give reason also.
$A$. Burning of wax
$B$. Melting of wax

The following diagram displays a chemical reaction. Observe it carefully and answer the following questions:
$(a)$ Identify the type of chemical reaction that will take place and define it. How will the colour of the salt change?
$(b)$ Write the chemical equation of the reaction that takes place.
$(c)$ Mention one commercial use of this salt.

$A$ solution of potassium chloride when mixed with silver nitrate solution, an insoluble white substance is formed. $(i)$ State two types of this reaction.