If $x = \frac{1}{2} \left( \sqrt{3} + \frac{1}{\sqrt{3}} \right)$,then the value of $\frac{\sqrt{x^2 - 1}}{x - \sqrt{x^2 - 1}}$ is equal to

The $emf$ (in $V$) of a Daniell cell containing $0.1 \ M$ $ZnSO_4$ and $0.01 \ M$ $CuSO_4$ solutions at their respective electrodes is
$(E_{Cu^{2+} / Cu}^{\circ} = +0.34 \ V; E_{Zn^{2+} / Zn}^{\circ} = -0.76 \ V)$

Which of the following statements is not correct regarding calcination?

Guard cells are helpful in:

The number of points at which the function $f(x) = |x - 0.5| + |x - 1| + \tan x$ does not have a derivative in the interval $(0, 2)$ is:

The molar enthalpies of combustion of $C_2H_{2(g)}$,$C_{(graphite)}$,and $H_{2(g)}$ are $-1300$,$-394$,and $-286 \ kJ \ mol^{-1}$,respectively. The standard enthalpy of formation of $C_2H_{2(g)}$ is ....... $kJ \ mol^{-1}$.