State whether the following statement is true or false:
Keeping food in airtight containers helps to slow down oxidation.

Write one example for each of the decomposition reactions carried out with the help of:
$(i)$ electricity
$(ii)$ heat
$(iii)$ sunlight
Give balanced chemical equations in each case.

In the double displacement reaction between aqueous potassium iodide and aqueous lead nitrate,a yellow precipitate of lead iodide is formed. While performing the activity if lead nitrate is not available,which of the following can be used in place of lead nitrate?

Balance the following chemical equations and identify the type of chemical reaction.
$(a)$ $TiCl_4(l) + Mg(s) \to Ti(s) + MgCl_2(s)$
$(b)$ $CaO(s) + SiO_2(s) \to CaSiO_3(s)$
$(c)$ $H_2O_2(l) \xrightarrow{UV} H_2O(l) + O_2(g)$

What happens when hydrogen gas is passed over heated copper oxide $(CuO)$?

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