(dissolving or reacting) . All gases are less dense than liquid water and will displace the water downwards. No good for soluble gases like ammonia, hydrogen chloride, nitrogen dioxide or sulphur dioxide. You can collect in inverted gas jar if bigger sample required.You have to watch for 'sucking back' effects. Answer   Hydrogen can be collected by the downward displacement of water because of two reasons: it is less dense than water, and so rises to the surface, and it â¦ is not very soluble in water, and so nearly all the gas can be collected because very little is dissolved in the water.
preserve - a domain that seems to be specially reserved for someone; medicine is no longer a male preserve. 1  arena, domain, sphere, orbit, area, field - a particular environment or walk of life; his social sphere is limited; it was a closed area of employment; he's out of my orbit.
Use the noun preservation to refer to the protection of something â especially from loss, injury, or danger. You might fight for the preservation of the woodlands near your house because of all the animals that live there. Preservation is also a process that keeps organic things from decomposing. If the preservation of the flowers in your prom corsage is important to you, you can dry the flowers to keep them from decaying. If you dry them, they'll probably last longer than your relationship with your high school boyfriend! The word preservation is often used when referring to historic preservation, which is the protection of buildings and sites of historic significance.