Question

identify arrows pointing to bonding electrons. a, b, d complete identify arrows pointing to nonbonding electrons. c complete identify arrows pointing to structures containing sigma bonds. a, b a, b, d c b, d done

Explanation:

Step1: Recall sigma - bond concept

Sigma bonds are the first type of bond formed in a covalent bond. Single bonds are always sigma bonds, and in double and triple bonds, one of the bonds is a sigma bond.

Step2: Analyze the structure

In the given structure of $HCOOH$ (formic acid), the $C - H$ bond (arrow b) is a single bond and thus a sigma - bond. The $C=O$ double bond has one sigma - bond (arrow a) and one pi - bond. The $C - O$ single bond (arrow d) is also a sigma - bond. Arrow c points to a non - bonding electron pair and not a bond.

Answer:

a, b, d