If $P_1$ is the partial pressure of a gas and $x_1$ is its mole fraction in a mixture,then the correct relation between $P_1$ and $x_1$ is:

In which of the following gas mixtures does Dalton's Law of Partial Pressure not apply? Why?
$(i)$ $CO_2 + O_2 + N_2$
$(ii)$ $CO + O_2$
$(iii)$ $NH_3 + HCl$
$(iv)$ $HCl + O_2$

$50 \ mL$ of each gas $A$ and gas $B$ takes $150$ and $200$ seconds respectively for effusing through a pinhole under similar conditions. If the molecular mass of gas $B$ is $36$,the molecular mass of gas $A$ will be:

$A$ neon-dioxygen mixture contains $64 \ g$ $O_2$ and $160 \ g$ $Ne$. If the total pressure is $25 \ bar$,calculate the partial pressure of dioxygen. (in $bar$)

What is the $SI$ unit of viscosity?

$A$ gaseous mixture of $3$ gases $A$, $B$ and $C$ has a pressure of $10 \,atm$. The total number of moles is $10$. If the partial pressures of gases $A$ and $B$ are $3 \,atm$ and $1 \,atm$ respectively, and the molar mass of gas $C$ is $2 \,g/mol$, calculate the weight of $C$ in the mixture. (in $\,g$)