Chemistry

Hydrogen

Question:

Calculate the strength of 5 volume H202

Answer:

5 volume H202 solution means that 1 L of 5 volume H202 on decomposition gives 5L of 02 at NTP.
ncert-exemplar-problems-class-11-chemistry-chapter-9-hydrogen-19

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Hydrogen

Q 1.

Describe the usefulness of water in biosphere and biological systems.

Q 2.

Show how H2O2 junctions both as a reducing and as an oxidising agent.

Q 3.

What type of elements form interstitial hydrides?

Q 4.

Which type of hydrides are generally non-stoichiometric in nature?

Q 5.

Complete the following reactions:
cbse-class-11th-chemistry-solutions-chapter-9-hydrogen-23

Q 6.

Which of the following equatibns depicts the oxidizing nature of H202?
(a) 2Mn04 + 6H+ + 5H202 → 2Mn2+ + 8H20 + 502
(b) 2Fe3+ + 2H+ + H202 → 2Fe2+ + 2H20 + 02
(c) 2I + 2H+ + H202 → I2 + 2H20
(d) KI04 + H202 → KI03 + H20 + 02

Q 7.

Give two advantages of using hydrogen over gasoline as a fuel.

Q 8.

If same mass of liquid water and a piece of ice are taken, then why is the density of ice less than that of liquid water?

Q 9.

Complete the following chemical reactions.
(i) PbS(s) + H2O2 (aq) ————->
(ii) MnO4 (aq) + H2O2 (aq) ————->
(iii) CaO(s) + H2O(g) ————->
(iv) AlCl3(g) + H2O(l)————->
(v) Ca3N2(S) + H2O(l) ————->
Classify the above into (a) hydrolysis, (b) redox and (c) hydration reactions.

Q 10.

How can saline hydrides remove traces of water from organic compounds?

Q 11.

What is the cause of bleaching action of H2O2?

Q 12.

Name a substance which can oxidise H2O2

Q 13.

How is  heavy water prepared? Compare its physical properties with those of ordinary water.

Q 14.

Dihydrogen reacts with dioxygen (02) to form water. Write the name and formula of the product when the isotope of hydrogen which has one proton and one neutron in its nucleus is treated with oxygen. Will the reactivity of both the isotopes be the same towards oxygen? Justify your answer.

Q 15.

What is water gas? How is it prepared?

Q 16.

Explain the following:
(i) Temporary hardness can remove by boiling
(ii) Soft water lathers with soap but hard water not.

Q 17.

Discuss the principle and method of softening of hard water by synthetic ion-exchange resins.

Q 18.

What is the use of hydrogen in the manufacture of Vanaspati Ghee?

Q 19.

Complete the following reactions:
(i)SiCl4 + LiAlH4 ————->
(ii)Mg3N2 + H2O ————->
(iii)NaH + CO —————–>

Q 20.

Write the names of isotopes of hydrogen. What is the mass ratio of these isotopes?

Q 21.

What is meant by ‘demineralised water’ and how can it be obtained?

Q 22.

What is zeolite?

Q 23.

Write two uses of interstitial hydrides.

Q 24.

Which compounds cause temporary hardness of water?

Q 25.

Some of the properties of water are described below. Which of them is/are not correct?
(a) Water is known to be universal solvent.
(b) Hydrogen bonding is present to a large extent in liquid water.
(c) There is no hydrogen bonding in the frozen state of water.
(d) Frozen water is heavier than liquid water.

Q 26.

Name the classes of hydrides to which H20, B2H6 and NaH belong.

Q 27.

Write one chemical reaction for the preparation of D202.

Q 28.

What causes the temporary and permanent hardness of water?

Q 29.

Give an example of an ionic hydride and a covalent hydride:

Q 30.

The oxide that gives H202 on treatment with dilute H2S04 is
(a) Pb02
(b) Ba02 -8H20
(c) Mn02
(d) Ti02

Q 31.

What is the importance of heavy water with regard to nuclear power generation ?

Q 32.

Account for the following:
(a) Can phosphorus with electronic configuration 3s2 3p3 form PH5?
(b) Water is responsible for moderation of body temperature. How?
(c) Hard water is not suitable for boilers as well as for laundary.

Q 33.

How do you expect the metallic hydrides to be useful for hydrogen storage? Explain.

Q 34.

What are metallic/interstitial hydrides? How do they differ from molecular hydrides?

Q 35.

Calculate the strength of 5 volume H202

Q 36.

Explain why HC1 is a gas and HF is a liquid.

Q 37.

Justify the position of hydrogen in the periodic table on the basis of its electronic configuration.

Q 38.

How can the production of dihydrogen obtained from ‘Coal gasification’ be increased?

Q 39.

What is meant by hard water?

Q 40.

The aqueous solution of H2O2 is acidic in nature. Explain with the help of example. Name two substances which catalyse the decomposition reaction of H2O2.

Q 41.

Consider the reactions
(A) H202 + 2HI → I2 + 2H20
(B) HOCl + H2O2 → H30+ + Cl‑ + 02
Which of the following statements is correct about H202 with reference to these reactions? Hydrogen peroxide is   _______      
(a) an oxidizing agent in both (A) and (B)
(b) an oxidizing agent in (A) and reducing agent in (B)
(c) a reducing agent in (A) and oxidizing agent in (B)
(d) a reducing agent in both (A) and (B)

Q 42.

Which of the following statement(s) is/are correct in the case of heavy water?
(a) Heavy water is used as a moderator in nuclear reactor.
(b) Heavy water is more effective as solvent than ordinary water.
(c) Heavy water is more associated than ordinary water.
(d) Heavy water has lower boiling point than ordinary water.

Q 43.

Hardness of water may be temporary or permanent. Permanent hardness is due to the presence of
(a) Chlorides of Ca and Mg in water
(b) Sulphate of Ca and Mg in water
(c) Hydrogen carbonates of Ca and Mg in water
(d) Carbonates of alkali metals in water.

Q 44.

Which of the following statements are correct?
(a) Elements of group 15 form electron deficient hydrides.
(b) All elements of group 14 form electron precise hydrides.
(c) Electron precise hydrides have tetrahedral geometries.
(d) Electron rich hydrides can act as Lewis acids.

Q 45.

Which of the following statements are correct?
(a) Hydrides of group 13 act as Lewis acids.
(b) Hydrides of group 14 are electron deficient hydrides.
(c) Hydrides of group 14 act as Lewis acids.
(d) Hydrides of group 15 act as Lewis bases.

Q 46.

Which of the following statements are correct?
(a) Metallic hydrides are deficient of hydrogen.
(b) Metallic hydrides conduct heat and electricity.
(c) Ionic hydrides do not conduct electricity in solid state.
(d) Ionic hydrides are very good conductors of electricity in solid state.

Q 47.

How can production of hydrogen from water gas be increased by using water gas shift reaction?

Q 48.

What do you understand by the term ‘auto-protolysis of water? What is its significance?

Q 49.

Discuss briefly de-mineralisation of water by ion exchange resin.

Q 50.

(i)Draw the gas phase and solid phase structure of H202.
(ii) H202 is a better oxidizing agent than water. Explain.