$A$ hydride of nitrogen which is acidic is

Which of the following is characterized by a cell wall made of peptidoglycan?

The number of common tangents to the two circles $x^2+y^2-8x+2y=0$ and $x^2+y^2-2x-16y+25=0$ is:

If $z = \sec^{-1}\left(\frac{x^4+y^4-8x^2y^2}{x^2+y^2}\right)$,then $x \frac{\partial z}{\partial x} + y \frac{\partial z}{\partial y}$ is equal to

When $H_2SO_4$ reacts with $PCl_5$,the obtained product is/are:

The image of the line $x+y-2=0$ in the $y$-axis is