In which of the following compounds is the ratio of the size of the anion to the size of the cation the smallest?

In the $Hoop$ process for the refining of $Al$,the molten materials form three different layers and remain separate during electrolysis because ..........

What are $\underline{A}, \underline{B}, \underline{C}$ in the following reactions?
$(I)$ $(CH_3 CO_2)_2 Ca \xrightarrow{\Delta} \underline{A}$
$(II)$ $CH_3 CO_2 H \xrightarrow[Red\ P]{HI} \underline{B}$
$(III)$ $2 CH_3 CO_2 H \xrightarrow{P_4 O_{10}} \underline{C}$
$\underline{A} \quad \underline{B} \quad \underline{C}$

If $\alpha, \beta, \gamma$ are the roots of $x^3-2x^2+3x-4=0$,then the value of $\alpha^2\beta^2+\beta^2\gamma^2+\gamma^2\alpha^2$ is

For a Poisson variate $X$, if $P(X=2)=3 P(X=3)$, then the mean of $X$ is :

Which of the following represents the correct order of the acidity in the given compounds?