One that cannot react directly with iron to form ferrous sulfide is ( ).

One of the following options that is not the cause of ferrous sulfide production is ( ).

The following statement about the physical properties of ferrous sulfide is incorrect ( ).

One that can react directly with iron to produce ferrous sulfide is ( ).

The chemical equation for hydrogen combustion is ( ).

The following statement about the use of hydrogen, incorrect is ( ).

The following statement about the chemistry of hydrogen, incorrect is ( ).

The following statement about the physical properties of hydrogen, incorrect is ( ).

The following substances in which the free nitrogen element is present are ( ).

One of the following options that is not used for nitrogen is ( ).

The toxic of the following is ( ).

What is not true about the following statement about superheated steam is ( ).

Water vapor at 1 atmosphere and 120 ℃ is called ( ).

Water vapor at 1 atmosphere and 100 ℃ is called ( ).

One of the following options that is not superheated steam is ( ).