The property of concentrated H₂SO₄ that makes it suitable for preparing HNO₃ is its

Explanation: In the laboratory, nitric acid (\(\ce{HNO3}\)) is prepared by heating sodium nitrate (\(\ce{NaNO3}\)) or potassium nitrate (\(\ce{KNO3}\)) with concentrated sulphuric acid (\(\ce{H2SO4}\)). The key property that makes concentrated \(\ce{H2SO4}\) suitable is that it has a very high affinity for water, i.e. it is a powerful dehydrating agent. This property drives the reaction forward because \(\ce{H2SO4}\) removes water from the system and allows \(\ce{HNO3}\) to distil off.

Check the options:

• Boiling point: not the reason here.
• Density: irrelevant to this preparation.
• Oxidizing properties: although \(\ce{H2SO4}\) is an oxidizing agent, that is not why it is used here.
• Dehydrating properties: correct. It removes water and drives the formation of nitric acid.