Why does a sharp glass edge become smooth on heating it up to its melting point in a flame? Explain which property of liquids is responsible for this phenomenon.

Equal weights of $CH_4$ and $H_2$ are mixed in an empty container at $25 \, ^oC$. The fraction of the total pressure exerted by $H_2$ would be

At $27^{\circ} C$, $500 \ mL$ of helium diffuses in $30 \ minutes$. What is the time (in hours) taken for $1000 \ mL$ of $SO_2$ to diffuse under the same experimental conditions?

Identify the incorrect statement among the following:

At a given temperature,the molar mass of gas $A$ is $4$. If it diffuses $3$ times faster than gas $B$,what is the molar mass of gas $B$?

At $290 \ K$,a vessel $(I)$ contains equal moles of three liquids $(A, B, C)$. The boiling points of $A, B$ and $C$ are $350 \ K, 373 \ K$ and $308 \ K$ respectively. Vessel $(I)$ is heated to $300 \ K$ and vapours were collected into vessel $(II)$. Identify the correct statements. (Assume vessel $(I)$ contains liquids and vapours and vessel $(II)$ contains only vapours)
$I.$ Vessel $- I$ is rich in liquid $B$
$II.$ Vessel $- II$ is rich in vapour of $C$
$III.$ The vapour pressures of $A, B, C$ in Vessel $(I)$ at $290 \ K$ follows the order $C > A > B$.