Hydrogen and s Block Elements Intext Questions with Answer NIOS

Hydrogen and s Block Elements Intext Questions with Answer NIOS National Institute of Open Schooling | NIOS

Hydrogen and s Block Elements Intext Questions with Answer NIOS

National Institute of Open Schooling (NIOS)
Sr. Secondary, Module-6
Lession-17: Hydrogen and s Block Elements Intext Questions with Answer NIOS


1. Name the isotopes of hydrogen.

The isotopes of hydrogen are protium 1H1, deuterium 1H2 or D and tritium 1H3 or T.

2. Name the isotope of hydrogen which is radioactive?

Tritium is the radio active isotope of hydrogen which has a mass number of 3 and atomic number 1.

3. Why is hydrogen used for filling balloons?

Because it is a lighter gas.

4. Which gas is produced, when hydrogen combines with carbon?

On strongly heating, carbon directly combines with hydrogen gas to form methane gas.
C + 2H2 → CH4

5. Name the gas which is used for the production of fertilizers.

Amonia gas is used for production of fertilizers (NH3).

6. How are vegetable oils changed into vegetable ghee?

Vegetable oils change into vegetable ghee when hydrogen is passed through the oils at 443K in presence of nickel as a catalyst.


1. Why does ice float on water?

Density of ice is less than water. Ice is actually about 9% less dense than water. Since the water is heavier, it displaces the lighter ice, causing the ice to float on the top of water.

2. What is heavy water? Write its important uses.

Water containing deuterium in place of ordinary hydrogen (protium) is termed as heavy water (D2O).
Uses of heavy water-
The heavy water is used in neutron moderator in types of nuclear reactors. In reactor, the heavy water will helps to retard the neutrons.
The heavy water is used in nuclear magnetic resonance.
The heavy water is widely used in organic chemistry.
The heavy water is used to check the metabolic rate in animals and humans by physiology and biology.
The heavy water is used for the production of tritium in small amounts from moderated reactor.

3. Give one method of preparation of hydrogen peroxide.

Laboratory Method of Preparation-
By the action of dilute mineral acids (H2SO4) on metallic peroxides (barium peroxide, sodium peroxide) When barium peroxide is acidified and the excess water is removed by the process of evaporation under reduced pressure, we obtain hydrogen peroxide.
BaO2.8H2O(s) + H2SO4(aq) → BaSO4(s) + H2O2(aq) + 8H2O(l)

4. Give two uses of hydrogen peroxide.

Hydrogen peroxide used as a bleaching agent and germicide or disinfectant.

5. How does hydrogen peroxide decolorize potassium permaganate?

Hydrogen peroxide reduces the permanganate to a colorless product.
2KMnO4(VII) + 3H2SO4 + 5H2O2 = 2MnSO4(II) + K2SO4 + 5O2 + 8H2O

6. Name the types of hydrides.

Three basic types of hydrides— ionic, metallic (Interstitial hydrides) and covalent.

7. NaH is covalent or ionic hydride?

NaH is an ionic hydride.


1. Name the important ores of sodium.

Sodium Carbonate - Na2CO3
Sodium Chloride -NaCl
Sodium Nitrate -NaNO3
Sodium Sulphate -Na2SO4

2. Arrange the alkali metals in order of increasing ionization enthalpy.

Order of increasing ionization enthalpy-
Cs < Rb < K < Na < Li

3. Which of the alkali metals forms only monoxide?

Lithium forms only one type of oxide, lithium monoxide Li2O.

4. Write down the chemical equation for the reaction of sodium with water.

2Na(s) + 2H2O → NaOH(aq) + H2(g)

5. What type of bond exists in the hydrides of alkali metals?

Ionic bond exists in the hydrides of alkali metals.

6. Name the element which forms (i) peroxide, (ii) superoxide.

Sodium and  potassium form peroxide and superoxide.

7. Write chemical equation when NaHCO3 is heated.

When sodium bicarbonate is heated, it decomposes into sodium carbonate and carbon dioxide.
NaHCO3 → Na2CO3 + CO2 + H2O.

8. Li+ resembles Mg2+. Why?

Because of diagonal relationship and polarizing power, Li+ resembles Mg2+.

9. Name the common ore of Mg.

Carnallite: KCl.MgCl2.6H2O.
Dolomite: CaMg(CO3)2
Magnesite: MgCO3).

10. Arrange the alkaline earth metals in order of increasing reactivity.

Increasing order of reactivity-
Be < Mg < Ca < Sr < Ba

11. Name an amphoteric oxide of alkaline earth metals.

Beryllium  oxide is amphoteric in nature.

12. Arrange the carbonates of alkaline earth metals in order of thermal stability.

The thermal stability of the carbonates increases with increase in the size of the cation . BeCO3 < MgCO3 < CaCO3 < SrCO3 < BaCO3

13. What is the biological role of Ca2+.

Ca2+ ions are important in blood clotting, to maintain the regular heartbeat.
It plays a significant role in the metabolism of nitrogen in plants.

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