question_answer 1)

Arrange benzene, n-hexme and ethyne in decreasing order of acidic behaviour. Also give reason for this behaviour.

Answer:

  The decreasing order of acidic strength: Hydro-carbon: Ethyne > Benzene > n-Hexane Type of orbital: \[\underset{sp}{\mathop{H-C\equiv \overset{sp}{\mathop{C}}\,-H}}\,\] \[\underset{s{{p}^{3}}}{\mathop{C{{H}_{3}}-{{(C{{H}_{2}})}_{4}}\overset{s{{p}^{3}}}{\mathop{C{{H}_{3}}}}\,}}\,\] s-Character: \[50%\] \[33.3%\] \[25%\]   The acidic character is linked with percentage of s-character. Greater the s-character, more is the electro negativity of the carbon atom and more will be the acidic character.