What can be seen when a strip of copper metal is placed in a solution of silver nitrate?

List two observations which you record while burning magnesium in air.

Solid calcium oxide reacts vigorously with water to form calcium hydroxide accompanied by liberation of heat. This process is called slaking of lime. Calcium hydroxide dissolves in water to form its solution called lime water. Which among the following is (are) true about slaking of lime and the solution formed?
$(i)$ It is an endothermic reaction
$(ii)$ It is an exothermic reaction
$(iii)$ The $pH$ of the resulting solution will be more than seven
$(iv)$ The $pH$ of the resulting solution will be less than seven

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

$A$ metal $P$,when exposed to moist air for a longer period of time,loses its shiny brown surface and gains a green coat. Why has this happened? Identify the metal. Write the name and chemical formula of this green-coloured compound. List two ways to prevent this process.

Give a reason why:
$(i)$ Why is a decomposition reaction called the opposite of a combination reaction?