$\lim _{x \rightarrow 0} \frac{\sin x \sin ^{-1} x}{x^2}$ is equal to

For $x \in \mathbb{R}$,the least value of $\frac{x^2-6x+5}{x^2+2x+1}$ is

According to molecular orbital theory,the total number of bonding electron pairs in $O_2$ is

The same retarding force is applied to stop a train. The train stops after $80 \ m$. If the speed is doubled,then the distance will be

What is the equivalent weight of hydrochloric acid in the given redox reaction?
$MnO_2 + 4HCl \to MnCl_2 + 2H_2O + Cl_2$
If the molar mass of hydrochloric acid is $M$.

The presence of a nitro group in a benzene ring.....