The number of single bonds in hexane molecule are:a. 18 b. 19c. 20 d. 21

Hexane is an alkane with the chemical formula C6H14.

Step 1: Identify the number of carbon (C) atoms in hexane. There are 6 carbon atoms in hexane.

Step 2: In an alkane, carbon atoms are connected by single bonds. So, there are 5 single bonds between the 6 carbon atoms.

Step 3: Each carbon atom also forms single bonds with hydrogen (H) atoms. Since each carbon atom forms 4 bonds in total and we have already accounted for the single bonds between carbon atoms, the remaining bonds must be with hydrogen atoms.

Step 4: For the 2 carbon atoms at the ends of the hexane molecule, there are 3 hydrogen atoms bonded to each, giving a total of 2*3 = 6 hydrogen bonds.

Step 5: For the 4 carbon atoms in the middle of the hexane molecule, there are 2 hydrogen atoms bonded to each, giving a total of 4*2 = 8 hydrogen bonds.

Step 6: Add up the total number of single bonds in hexane. This is the sum of the carbon-carbon bonds and the carbon-hydrogen bonds. So, the total number of single bonds in hexane is 5 (C-C bonds) + 6 (C-H bonds at the ends) + 8 (C-H bonds in the middle) = 19.

So, the correct answer is b. 19.