# Heat of formation of $CO\: and \: CO_2$ are - 26.4 and -94.0 kcal/mole respectively. What is the heat of combustion of $CO$ in kcals ?

$\begin {array} {1 1} (1)\;+26.4 & \quad (2)\;120.6 \\ (3)\;-67.6 & \quad (4)\;135.2 \end {array}$