Class 11 Chemistry - Chapter Hydrogen NCERT Solutions | Describe the structure of the common for

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

Compare the structures of H₂O and H₂O₂.

Write chemical reactions to show the amphoteric nature of water.

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

Arrange the following

(i) CaH₂, BeH₂ and TiH₂ in order of increasing electrical conductance.

(ii) LiH, NaH and CsH in order of increasing ionic character.

(iii) H-H, D-D and F-F in order of increasing bond dissociation enthalpy.

(iv) NaH, MgH₂ and H₂O in order of increasing reducing property.

What do you understand by the term “non-stoichiometric hydrides”? Do you expect this type of the hydrides to be formed by alkali metals? Justify your answer.

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

What causes the temporary and permanent hardness of water?

How does H₂O₂ behave as a bleaching agent?

Why does hydrogen occur in a diatomic form rather than in a monoatomic form under normal conditions?

How do you account for the formation of ethane during chlorination of methane?

What are hybridisation states of each carbon atom in the following compounds ?

(i) CH₂=C=O,

(ii) CH₃CH=CH₂,

(iii) (CH₃)₂CO,

(iv) CH₂=CHCN,

(v) C₆H₆

What will be the minimum pressure required to compress 500 dm³ of air at 1 bar to 200 dm³ at 30°C?

What are the common physical and chemical features of alkali metals?

Calculate the molecular mass of the following:
(i) H₂O
(ii) CO₂
(iii) CH₄

Assign oxidation number to the underlined elements in each of the following species:

(a) NaH₂PO₄

(b) NaHSO₄

(c) H₄P₂O₇

(d) K₂MnO₄

(e) CaO₂

(f) NaBH₄

(g) H₂S₂O₇

(h) KAl(SO₄)₂.12 H₂O

What is the basic theme of organisation in the periodic table?

Explain the formation of a chemical bond.

Choose the correct answer. A thermodynamic state function is a quantity
(i) used to determine heat changes
(ii) whose value is independent of path
(iii) used to determine pressure volume work
(iv) whose value depends on temperature only.

A liquid is in equilibrium with its vapour in a sealed container at a fixed temperature. The volume of the container is suddenly increased.
a) What is the initial effect of the change on vapour pressure?
b) How do rates of evaporation and condensation change initially?
c) What happens when equilibrium is restored finally and what will be the final vapour pressure?

Define electronegativity. How does it differ from electron gain enthalpy?

Ionic product of water at 310 K is 2.7 x 10^-14. What is the pH of neutral water at this temperature?

At 473 K, equilibrium constant K_c for decomposition of phosphorus pentachloride, PCl₅ is 8.3 ×10^-3. If decomposition is depicted as,

PCl₅ (g) ↔  PCl₃ (g) + Cl₂ (g)          Δ_rH⁰ = 124.0 kJ mol^–1

(a) write an expression for Kc for the reaction.

(b) what is the value of Kc for the reverse reaction at the same temperature ?

(c) what would be the effect on K_c if (i) more PCl5 is added (ii) pressure is increased (iii) the temperature is increased ?

Draw formulas for the first five members of each homologous series beginning with the following compounds.

(a) H-COOH

(b) CH₃COCH₃

(c) H-CH=CH₂

What do you mean by green chemistry? How will it help decrease environmental pollution?

Prefixes Multiples
(i) micro 10⁶
(ii) deca 10⁹
(iii) mega 10^–6
(iv) giga 10^–15
(v) femto 10

Classify the following reactions in one of the reaction type studied in this unit.

(a) CH₃CH₂Br   +   HS-  →  CH₃CH₂SH  +  Br-

(b) (CH₃)₂C = CH₂  +   HCl  →  (CH₃)₂ClC-CH₃

(c) CH₃CH₂Br  +  HO-   →  CH₂ = CH₂  +  H₂O  +  Br-

(d) (CH₃)₃C  -  CH₂OH  +  HBr   →   (CH₃)₂CBrCH₂CH₃  +  H₂O

Arrange the following type of radiations in increasing order of frequency:

(a) radiation from microwave oven

(b) amber light from traffic signal

(c) radiation from FM radio

(d) cosmic rays from outer space and

(e) X-rays.

Differentiate between the principle of estimation of nitrogen in an organic compound by

(i) Dumas method and

(ii) Kjeldahl's method.

Express the following in the scientific notation:
(i) 0.0048
(ii) 234,000
(iii) 8008
(iv) 500.0
(v) 6.0012