Olefins can be hydrogenated by

$H_{3}PO_{3}$ can be represented by structures $1$ and $2$ shown below. Can these two structures be taken as the canonical forms of the resonance hybrid representing $H_{3}PO_{3}$? If not,give reasons for the same.

The thermo emf of a thermocouple is given by $E = aT + bT^2$,where $\frac{a}{b} = -200^{\circ}C$. If the cold junction is kept at $30^{\circ}C$,then the inversion temperature is ($\varepsilon$ in volt,$T$ in centigrade). (in $K$)

$\int_0^{\pi / 2} \frac{d x}{1+\tan ^3 x}$ is equal to :

Let $\alpha \neq 1$ be a real root of the equation $x^3-ax^2+ax-1=0$,where $a \neq -1$ is a real number. Then,a root of this equation,among the following,is

Selection is a method related to which of the following?