How many covalent bonds are present in molecules of butane$C_4{H}_{10}$?

Butane is an alkane, having the chemical formula $C_4{H}_{10}$ which a hydrocarbon that consists of 4 carbon atoms and 10 hydrogen atoms. Its structure is shown below-

From the structure, it is clear that there are $3C-C$ covalent bonds. Also, there are $10C-H$-H Covalent bonds. So total covalent bonds in $C_4{H}_{10}=13.$.

Hence, the number of covalent bonds in the molecule of Butane, $C_4{H}_{10}$, is 13.