Which of the following pairs is not correctly matched?

Write the structures of the following compounds:
$(i)$ $\alpha$-Methoxypropionaldehyde
$(ii)$ $3$-Hydroxybutanal
$(iii)$ $2$-Hydroxycyclopentanecarbaldehyde
$(iv)$ $4$-Oxopentanal
$(v)$ Di-sec-butyl ketone
$(vi)$ $4$-Fluoroacetophenone

What is the $IUPAC$ name of mesityl oxide?

State True or False for the following statements:
$(i)$ Acetone is a propanone and there is an amide group in it.
$(ii)$ Acetone is dimethyl ketone.
$(iii)$ The formula of acetone is $CH_3COCH_3$.
$(iv)$ Acetone possesses a carbonyl group.

Explain the bond formation and structure of the carbonyl group with a suitable diagram.

Explain $\sigma$ and $\pi$-bond,and planarity and their bond angles in the carbonyl group.