At what temp will a solid melt

Identifying limitations of kinetic-molecular theorya chemist is studying the properties of a gas under various conditions. he observes that when the gas is at room temperature and low pressure, it behaves as an ideal gas. when the gas is cooled to 10 kelvin and is placed under high pressure, however, it deviates significantly from an ideal .

Iknow #2 is d. i just need to know why

Which step in naming unsaturated hydrocarbons is used for alkenes but not alkynes