Write the equations showing ambiphilic nature of the following molecule?

$\mathrm{H}-\mathrm{F}$

Which one of the following is a better nucleophile and why?

Arrange the following compounds for their acidic strength order.

Which of the following is not an aromatic compound?

The greater volatility of $2$-Nitrophenol, compared with $4$-Nitrophenol isomer is attributed to:

Basic strength of 

will be in order -