Calculate the number of $\mathrm{Cl}^{-}$ions in 222 g unhydrous calcium chloride?

(At. mass $\mathrm{Ca}=40, \mathrm{Cl}=35.5$ )

Which from following mixtures exhibits positive deviation from Raoult's law?

What is the difference in oxidation number of Mn in $\mathrm{KMnO}_4$ and $\mathrm{MnO}_2$ ?

Calculate the work done in joule if 2 moles of an ideal gas expand isothermally from $15.5 \mathrm{dm}^3$ to $20 \mathrm{dm}^3$ at constant pressure 1 atm .