Nitrous oxide will stay in the atmosphere the longest.
Concentrated sulfuric acid is used to promote acid catalyzed dehydration because it has little water.This favor the forward reaction.sulfuric acid acts as as proton source to enable loss of leaving group in forward reaction and electrophile addition in reverse reaction.
<span><span>KaAcid</span><span><span>1.0 * 109</span>Hydrobromic acidHBr</span><span><span>1.3 * 106</span>Hydrochloric acidHCl</span><span><span>1.0 * 103</span>Sulfuric acid<span>H2SO4</span></span><span><span>2.4 * 101</span>Nitric acid<span>HNO<span>3</span></span></span></span>
