Answer:
1 atm
Explanation:
The normal boiling point of a liquid is temperature at which the vapour pressure of the liquid equals 1 atm.
If the normal boiling point of cyclohexane is 81.0 °C, the vapour pressure of the liquid is 1 atm.
The graph below shows that the vapour pressure of cyclohexane reaches 1 atm at about 81 °C.
