Hydrogen Quiz - ICSE Class 11 Chemistry
Free practice quiz: Hydrogen (ICSE Class 11 Chemistry). 43 multiple-choice questions with answers and explanations. Play online, no sign-up needed.
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Which of the following isotopes of hydrogen is radioactive and possesses an unstable nucleus?
- Protium
- Deuterium
- Tritium
- All of the above
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Answer: C. Tritium
Protium (¹H) and Deuterium (²H) are stable isotopes of hydrogen. Tritium (³H) is a radioactive isotope with a half-life of about 12.3 years, meaning its nucleus is unstable.
What is the primary reason for the difference in reactivity between protium and deuterium in many chemical reactions?
- Mass difference
- Electronegativity difference
- Bond strength difference
- Ionic radius difference
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Answer: C. Bond strength difference
The difference in mass between protium and deuterium leads to a difference in zero-point energy and vibrational frequencies. This results in a difference in the strength of bonds formed by H and D. The H-X bond is generally weaker and easier to break than the D-X bond, leading to kinetic isotope effects.
Which type of hydride is known to be an excellent reducing agent and is often used in organic synthesis?
- Ionic hydrides
- Covalent hydrides
- Metallic hydrides
- Complex hydrides (e.g., NaBH₄, LiAlH₄)
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Answer: D. Complex hydrides (e.g., NaBH₄, LiAlH₄)
Complex hydrides like sodium borohydride (NaBH₄) and lithium aluminum hydride (LiAlH₄) are powerful reducing agents due to the presence of the hydride ion (H⁻) in a reactive form. Ionic hydrides also contain H⁻ but are less soluble and less reactive in organic solvents.
Which process is used to obtain hydrogen from coal?
- Gasification
- Pyrolysis
- Combustion
- Carbonation
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Answer: A. Gasification
Coal gasification involves reacting coal with steam and oxygen at high temperatures to produce syngas, which is primarily a mixture of carbon monoxide and hydrogen. The water-gas shift reaction is then used to increase the hydrogen content.
Water is called the 'universal solvent' primarily due to its:
- High viscosity
- Low surface tension
- Polar nature and ability to form hydrogen bonds
- Non-polar structure
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Answer: C. Polar nature and ability to form hydrogen bonds
Water's polarity allows it to dissolve ionic compounds by separating ions through ion-dipole interactions. Its ability to form extensive hydrogen bonds with itself and with other polar molecules also contributes to its excellent solvency.