Which of the following pairs is incorrectly matched?

The correct order of ionisation energy of $C, N, O, F$ is

The number of molecules in $16 \ g$ of methane is

The angle of a prism is $A.$ One of its refracting surfaces is silvered. Light rays falling at an angle of incidence $2A$ on the first surface return back through the same path after suffering reflection at the silvered surface. The refractive index $\mu$ of the prism is

Both the blocks shown in the figure have mass $m$ and are moving with constant velocity in the directions shown. They are in a resistive medium which exerts an equal constant force $F$ on both blocks in the direction opposite to their velocity. The tension in the string connecting them is (Neglect friction):

What is the product formed when benzylamine reacts with nitrous acid?