What is the product formed when sodium reacts with an excess of oxygen/air?

Lead pipes are not used for carrying drinking water because:

$P \xrightarrow{\Delta } Q$ (metallic solid) $+ R \uparrow + S \uparrow$
$X \xrightarrow{\Delta } Y$ (amphoteric oxide) $+ R \uparrow + S \uparrow$
$P$ and $X$ are respectively:

Which of the following statements is not true for most of the alkali metals?

Match List-$I$ with List-$II$ :

List-$I$	List-$II$
$(a)$ $NaOH$	$(i)$ Acidic
$(b)$ $Be(OH)_{2}$	$(ii)$ Basic
$(c)$ $Ca(OH)_{2}$	$(iii)$ Amphoteric
$(d)$ $B(OH)_{3}$
$(e)$ $Al(OH)_{3}$

Choose the most appropriate answer from the options given below :

Which among the following is used as a source of oxygen in submarines in emergency breathing apparatus?