The degree of dissociation of $100 \mathrm{mL}$ of pure water at $25° \mathrm{C}$ is

For the following reaction:$$\begin{gathered} \begin{array}{ccc} 2\mathrm{A} & + & \mathrm{B} \to \mathrm{product}\end{array} \\ \begin{array}{ccc}10 \mathrm{mol} {\mathrm{L}}^{-1}& & 2 \mathrm{mol} {\mathrm{L}}^{-1}\end{array} \left(\mathrm{Initial} \mathrm{concentration}\right) \end{gathered}$$

${\mathrm{t}}_{1/2}$ of the overall reaction is the time when 

From the following half cells, a galvanic cell is made,

$\begin{array}{lll}{\mathrm{A}}^{2+}\left(\mathrm{aq}\right)+2{\mathrm{e}}^{-}\to \mathrm{A}\left(\mathrm{s}\right)& \dots & {\mathrm{E}}_1^0=0.8\mathrm{V}\end{array}$

$\begin{array}{lll}\mathrm{B}\left(\mathrm{s}\right)\to {\mathrm{B}}^{3+}\left(\mathrm{aq}\right)+3{\mathrm{e}}^{-}& \cdots & {\mathrm{E}}_2^0=-0.3\mathrm{V}\end{array}$

The ${\mathrm{E}}^0$ cell is

An inert gas is added to the following equilibrium,

$\mathrm{A}\left(\mathrm{s}\right)+2\mathrm{B}\left(\mathrm{g}\right)\rightleftharpoons 3\mathrm{C}\left(\mathrm{g}\right)$ at constant pressure. The equilibrium 

In a successive radioactive disintegration

$$\begin{gathered} \mathrm{A}\stackrel{{\lambda }_1}{⟶}\mathrm{B}\stackrel{{\lambda }_2}{⟶} \\ {\mathrm{N}}_{1 }{\mathrm{N}}_2 \end{gathered}$$ $\mathrm{C}$$...$  Number of nuclides after time $\mathrm{t}$

Which of the following expressions is correct at steady state condition?