What is the hybridization of $C$ atoms in graphite?

Predict the hybridization of each carbon in the molecule of the organic compound given below. Also,indicate the total number of sigma $(\sigma)$ and pi $(\pi)$ bonds in this molecule.
$HC \equiv C-CO-CH_2-COOH$

The carbon atoms in an acetylene molecule are in which state of hybridisation?

The hybridisation of $Xe$ and the number of lone pairs of electrons on it in $XeF_6$ are

Suggest reasons why the $B-F$ bond lengths in $BF_3\ (130\ pm)$ and $BF_4^-\ (143\ pm)$ differ.

Identify the pair of molecules in which the central atom has the same hybridization.