question_answer

Which of following statement is true?

A) Absolutely pure water does not contain any ions

B) London forces is directly proportional to more number of loosely held electron

C) Allene is polar due to its non-planar structure

D) \[C{{H}_{3}}OC{{H}_{3}}\] is less volatile than \[{{C}_{2}}{{H}_{5}}OH\] due to higher molecular weight.

Correct Answer: B

Solution :

[b]

(1) \[{{H}_{2}}O\rightleftharpoons {{H}^{+}}+O{{H}^{-}}\]

\[{{K}_{w}}={{10}^{-14}}\] at \[{{25}^{o}}\]

Even in conductivity water \[({{H}_{2}}O)\] is found to be dissociated into \[{{H}^{+}}\] and \[O{{H}^{-}}\].

(2) More the number of loosely held electron, greater will be their tendency for being polarized deformed i.e., the magnitude of formal charge increases, hence London forces increases.

(3) \[{{H}_{2}}C=C=C{{H}_{2}}\]

(Non planar) \[{{\mu }_{D}}=0\]

(4) In \[C{{H}_{3}}COC{{H}_{3}}\] there is no H-bonding hence more volatile, while in \[{{C}_{2}}{{H}_{5}}OH\] intermolecular H-bonding is present hence less volatile, due to association.