In which of the following molecule/ion all the bonds are not equal?

1.  XeF4

2. BF4-

3. C2H4

4. SiF4

 
Hint: Sigma bond and pie bond both have a different bond length
 
Step 1:
 
Find the type of bonds in the given molecules.
 
 XeF44bp+2lpsquare planarall bonds are equal
 
BF4-4bp+0lptetrahedral (all bonds are equal)
 
C2H4C=C bond is not equal to C-H bond
 
SiF44bp+0lptetrahedral (all bonds are equal)
 
Step 2:
 
Hence, in C2H4  all the bonds are not equal.