The increasing order of the strength of hydrogen bond in the following mentioned linkages is:

(i) $\mathrm{O}-\mathrm{H}\cdots \mathrm{S}$

(ii) $\mathrm{S}-\mathrm{H}\cdots \mathrm{O}$

(iii) $\mathrm{F}-\mathrm{H}\cdots {\mathrm{F}}^{-}$

(iv) $\mathrm{F}-\mathrm{H}\cdots \mathrm{O}$

Select the correct option by assigning true (T) and false (F) for the following statements.

(a) In ${\mathrm{IF}}_7$, iodine is in the super octet state.

(b) ${\mathrm{BF}}_3$ is a hypervalent compound.

(c) $\mathrm{\pi }-$bond is cylindrically symmetrical.

In the structure of ${\mathrm{ClF}}_3$, the number of significant repulsions is

(If $\mathrm{lp}-\mathrm{lp}=\mathrm{x}, \mathrm{lp}-\mathrm{bp}=\mathrm{y}, \mathrm{bp}-\mathrm{bp}=\mathrm{z},$ then $\mathrm{x}+\mathrm{y}+\mathrm{z}=?$):