A.Sigma electron density of C– H bond in acetylene✓ Correct
B.Acetylene has only open hydrogen in each carbon
C.Acetylene contains least number of hydrogens
D.Acetylene belongs to the class of alkynes with
Explanation
The acidity of acetylene or 1-alkynes can be explained on the basis of molecular orbital concept according to which formation of C – H bond in acetylene involves sp hybridised carbon atom.