The decreasing order of acidic character among ethane(I), ethene(II), ethyne(III) and propyne (IV) is:

Options

A. (I)gt(II)gt(III)gt(IV)
B. (II)gt(III)gt(I)gt(IV)
C. (III)gt(IV)gt(II)gt(I)
D. (IV)gt(III)gt(II)gt(I)

Answer

C

Explanation

The correct order of decreasing acidity is :
`{:(CH -= CH gt CH -= C -CH_3 gt CH_2 = CH_2 gt CH_3 - CH_3),(" "(III)" "(IV)" "(II)" "(I)):}`
Hydrogen atoms attached to sp-hybridised carbon-atom are most acidic, followed by those attached to `sp^2` -hybridised carbon-atom, and those attached to `sp^3` -hybridised carbon are least acidic.