What is the bond angle observed in the $H-C-H$ bond of ethane (in $^{\circ}$)?

Explain the bond formation in $BeCl_{2}$ and explain why $BeCl_{2}$ is linear.

Determine the hybridization of the sulfur atom in the $SO_3$ molecule.

Match the following:

List-$I$	List-$II$
$(a)$ $SF_6$	$(i)$ $sp^3d^2$
$(b)$ $PCl_5$	(ii) $sp^3d$
$(c)$ $XeF_4$	(iii) $sp^3d^3$
$(d)$ $IF_7$	(iv) $sp^3d^2$

The correct answer is:

In which of the following sets of molecules is the hybridisation of the central atoms different?

Which of the underlined atoms in the molecules shown below have $sp$-hybridization?
$(u) H_2\underline{C}=CH-CH_3$
$(v) CH_2=\underline{C}=CHCl$
$(w) CH_3-\underline{C}H_2^+$
$(x) H-C \equiv C-H$
$(y) CH_3-\underline{C} \equiv N$
$(z) (CH_3)_2C=\underline{N}-NH_2$