What is the $B-F$ bond order in $BF_3$?

Consider the following gaseous equilibria with equilibrium constants $K_{1}$ and $K_{2}$ respectively.
$SO_{2(g)} + \frac{1}{2} O_{2(g)} \rightleftharpoons SO_{3(g)}$
$2 SO_{3(g)} \rightleftharpoons 2 SO_{2(g)} + O_{2(g)}$
The equilibrium constants are related as

When a point source of monochromatic light is at a distance of $0.2\, m$ from a photoelectric cell,the cut-off voltage and the saturation current are $0.6\, V$ and $18\, mA$ respectively. If the same source is placed $0.6\, m$ away from the photoelectric cell,then:

Which of the following halides is the most stable?

Which of the following is a polyamide?

If $y = \sin(m \sin^{-1} x)$,then $(1 - x^2) y_2 - x y_1$ is equal to (Here,$y_n$ denotes $\frac{d^n y}{dx^n}$)