Chemistry - Study Mode
[#961] Which of the following gases will effuse out of football bladder most quickly ?
Correct Answer
(B) H 2
Explanation
Solution: Hydrogen gas(H 2 ) will effuse out of football bladder most quickly.
[#962] The property of hydrogen which distinguishes it from alkali metals is
Correct Answer
(D) Its non-metallic character
Explanation
Solution: The property of hydrogen which distinguishes it from alkali metals is that hydrogen is a non - metal while all other members of group 1( alkali metals ) are metals.
[#963] Hydrogen is not found in atmosphere because
Correct Answer
(B) It is the lightest gas
Explanation
Solution: Hydrogen is a chemical element with symbol H and atomic number 1. With an average atomic weight of 1.00794 u (1.007825 u for hydrogen-1), hydrogen is the lightest element and its monatomic form (H 1 ) is the most abundant chemical substance, constituting roughly 75% of the Universe’s baryonic mass. Nonremnant stars are mainly composed of hydrogen in its plasma state. Air is the name given to the atmosphere used in breathing and photosynthesis. Dry air contains roughly (by volume) 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.039% carbon dioxide, and small amounts of other gases. Air also contains a variable amount of water vapor, on average around 1%. Naturally occurring atomic hydrogen is rare on Earth because hydrogen readily forms covalent compounds with most elements and is present in the water molecule and in most organic compounds.
[#964] Carbon monoxide is an inflammable gas. Which one of the following is also inflammable?
Correct Answer
(D) Hydrogen
Explanation
Solution: At standard temperature and pressure, hydrogen is a colourless, odorless, tasteless, non-toxic, nonmetallic, highly combustible diatomic gas with the molecular formula H 2 . Naturally occurring atomic hydrogen is rare on Earth because hydrogen readily forms covalent compounds with most elements and is present in the water molecule and in most organic compounds. Hydrogen plays a particularly important role in acid-base chemistry with many reactions exchanging protons between soluble molecules. Hydrogen gas (dihydrogen or molecular hydrogen) is highly flammable and will burn in air at a very wide range of concentrations between 4% and 75% by volume. The enthalpy of combustion for hydrogen is 286 kJ/mol. Pure hydrogen-oxygen flames emit ultraviolet light and are nearly invisible to the naked eye, as illustrated by the faint plume of the Space Shuttle Main Engine compared to the highly visible plume of a Space Shuttle Solid Rocket Booster.
[#965] When Hydrogen starts burning in air, it produces ?
Correct Answer
(B) Water
Explanation
Solution: In a flame of pure hydrogen gas, burning in air, the hydrogen (H 2 ) reacts with oxygen (O 2 ) to form water (H 2 O) and releases heat.