The sum of $\pi$-bonds present in peroxodisulphuric acid and pyrosulphuric acid is:

In which of the following compounds is the octet complete $(C)$ or incomplete $(IC)$ for all atoms?
$Al_2Cl_6$ $-$ $Al_2(CH_3)_6$ $-$ $AlF_3$ $-$ Dimer of $BeCl_2$ $-$ Dimer of $BeH_2$
(Note: $C$ for complete octet and $IC$ for incomplete octet.)

The number of $\sigma$ bonds,$\pi$ bonds and lone pair of electrons in pyridine,respectively are:

Write Lewis dot symbols for atoms of the following elements: $Mg, Na, B, O, N, Br$.

Which of the following compounds $CANNOT$ act as a Lewis base?

Match the following molecules in Column $I$ with the number of lone pairs on their central atom in Column $II$.

Column $I$ (Molecules)	Column $II$ (Number of lone pairs on central atom)
$A. \ NH_3$	$1. \ \text{Two}$
$B. \ H_2O$	$2. \ \text{Three}$
$C. \ XeF_2$	$3. \ \text{Zero}$
$D. \ CH_4$	$4. \ \text{Four}$
	$5. \ \text{One}$