Answer
a) Tetrahedral geometry
b) Trigonal planar geometry
c) linear geometry
Work Step by Step
We now the electronic configuration of the carbon is 1$s^{2}$2$s^{2}$2$p^{2}$.
It has 1 electron pair in 2s and 2 un-paired electron in the 3 2p orbitals
single bond has 1 σ bond.
double bond has 1 σ bond and 1 π bond.
triple bond has 1 σ bond and 2 π bonds.
a) So a carbon with 4 single bonds has the three 2p orbitals and a 2s orbital hybridized to make 4 equivalent s$p^{3}$ hybridzed and thus forms tetrahedral shape geometry.
b) similarly , the hybridization here would be s$p^{2}$ and shape will be trigonal planar.
c) one single bond and one triple bond - he hybridization here would be s$p^{1}$ and shape will be linear.
