Answer
See the answer below.
Work Step by Step
a) Angles 1 and 3: 120°, the geometry around the central carbon is trigonal planar (3 ligands, no lone pair).
Angle 2: 180°, the geometry around the central carbon is linear (2 ligands, no lone pair).
b,c) The double bond because bond length decreases and bond strength increases with bond order.
d) Since nitrogen is more electronegative than carbon, which is more electronegative than hydrogen, the nitrogen is on the negative end and the hydrogens are the positive ends.
e) The C$\equiv$N bond because it has the biggest difference in electroneutrality between the ligands.
f) This molecular is polar because it has polar bonds that don't cancel out in the vectorial sum.
