Average bond order of $\mathrm{C}-\mathrm{C}$ bond in ${\mathrm{C}}_6{\mathrm{H}}_6$ is: 

Which of the following overlaps is incorrect [assuming z-axis to be the internuclear axis] 

(a) $2{\mathrm{p}}_{\mathrm{y}}+2{\mathrm{p}}_{\mathrm{y}}\to \pi 2{\mathrm{p}}_{\mathrm{y}}$   

(b) $2{\mathrm{p}}_{\mathrm{z}}+2{\mathrm{p}}_{\mathrm{z}}\to \mathrm{\sigma } 2{\mathrm{p}}_{\mathrm{z}}$
(c) $2{\mathrm{p}}_{\mathrm{x}}+2{\mathrm{p}}_{\mathrm{x}}\to \mathrm{\pi } 2{\mathrm{p}}_{\mathrm{x}}$
(d) $1\mathrm{s}+2{\mathrm{p}}_{\mathrm{y}}\to \mathrm{\pi } (1\mathrm{s}-2\mathrm{py})$

Draw the Lewis dot structure of the following:

${\mathrm{BF}}_3$

Draw the Lewis dot structure of the following:

${\left[\mathrm{B}(\mathrm{OH}{)}_4\right]}^{-}$