Which of the following pairs is incorrectly matched?

If three points $A, B$ and $C$ have position vectors $(1, x, 3), (3, 4, 7)$ and $(y, -2, -5)$ respectively and if they are collinear, then $(x, y)$ is

When $tert$-butyl bromide is heated with silver fluoride,the major product obtained is:

Which of the following structures contains its own $DNA$?

The formula of sodium nitroprusside is .........

$(\tan ^{-1} x)^2+(\cot ^{-1} x)^2=\frac{5 \pi^2}{8} \Rightarrow x=$