In what respect will two dry samples of nitrogen gas differ from each other if sample 1 is prepared by completely removing CO₂ and O₂ from air, and sample 2 is prepared by passing purified nitrogen(i)oxide over heated copper? sample 1 is

• A purer than sample 2
• B slightly denser than sample 2
• C in all respects the same as sample 2
• D colourless but sample 2 has a light brown colour
• E slightly less reactive than sample 2