$3.42 \, g$ of sucrose are dissolved in $18 \, g$ of water in a beaker. The number of oxygen atoms in the solution are

Mention the name given to the number of $6.022 \times 10^{23}$ particles.

$A$ change in the physical state can be brought about:

State whether the following statement is true or false:
The atomicity of phosphorus is $5$ and that of sulphur is $6$.

$(a)$ In this crossword puzzle (Fig),names of $11$ elements are hidden. Symbols of these are given below. Complete the puzzle.
$1. Cl$
$2. H$
$3. Ar$
$4. O$
$5. Xe$
$6. N$
$7. He$
$8. F$
$9. Kr$
$10. Rn$
$11. Ne$
$(b)$ Identify the total number of inert gases,their names,and symbols from this crossword puzzle.

Write the names of the compounds represented by the following chemical formulae:
$(i)$ $NaBr$
$(ii)$ $Al_{2}O_{3}$
$(iii)$ $Zn(NO_{3})_{2}$
$(iv)$ $HCl$
$(v)$ $NaCl$
$(vi)$ $CaCO_{3}$