The ratio between kinetic energy and the total energy of the electrons of a hydrogen atom according to Bohr's model is

$A$ man pushes a wall and fails to displace it. He does:

The $pK_a$ of a weak acid $HA$ is $4.5$. The $pOH$ of an aqueous buffered solution of $HA$ in which $50\%$ of the $HA$ acid is ionized is

Write the resonance structures of $CO_3^{2-}$ and $HCO_3^-$.

Identify the correct order in which the covalent radius of the following elements increases: $(I)$ $Ti$,$(II)$ $Ca$,$(III)$ $Sc$.

Statement$-1$ : Toluene is more reactive than benzene in chlorination.
Statement$-2$ : During the nitration of Toluene $\stackrel{\oplus}{ N } O _2$ acts as electrophile.