Explain the fire polishing of glass.

The radius of the $Na^{+}$ ion is $95 \ pm$ and that of $Cl^{-}$ ion is $181 \ pm$. Predict the coordination number of $Na^{+}$ in $NaCl$.

$A$ beaker containing a mixture of liquid $A$ and liquid $B$,in equilibrium with each other,is cooled very slowly. If point '$D$' on the graph is where solidification of both liquids is complete,how many different phases co-exist along line '$C D$' if freezing points of liquid $B$ and liquid $A$ are $-25^{\circ} C$ and $-78^{\circ} C$ respectively?

If the distance between two gas molecules becomes half,what change occurs in the London dispersion forces?

The density of gas $A$ is twice that of $B$. The molecular mass of $A$ is half of $B$. The partial pressure ratio of $A$ and $B$ is

When $0.0168 \, mol$ of $O_2$ obtained from the decomposition of $KClO_3$ is collected over water at $25 \, ^\circ C$,the volume is $428 \, mL$ and the pressure is $754 \, mm$. What is the water vapor pressure at $25 \, ^\circ C$ in $mm$?