# NEET Chemistry The p-Block Elements (XII) Questions Solved

BOARD

How would you account for the following:

(i) $N{F}_{3}$ is an exothermic compound but $NC{l}_{3}$ is not.

(ii) The acidic strength of compounds increases in the order:

$P{H}_{3}<{H}_{2}S.

(iii) $S{F}_{6}$ is kinetically inert.

(i) F is more electronegative than Cl.

The difference in the electronegativity between N and F is much more than the difference between electronegativity of N and Cl. So there is need of much more energy to break the N-F bond.

(ii) As the electronegativity increases in the same period from left to right so their electronegativity are in the increasing order, P < S < Cl.

In the same way the acid strength is also in the increasing order i.e., $P{H}_{3}<{H}_{2}S

(iii)Because $S{F}_{6}$ is showing steric hindrance due to 6 (six) fluorine atoms which make it unable to react further with any other atom.

Difficulty Level:

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