Class 11 Chemistry - Chapter Environmental Chemistry NCERT Solutions | What do you mean by Biochemical Oxygen D

Carbon monoxide gas is more dangerous than carbon dioxide gas. Why?

What are the harmful effects of photochemical smog and how can they be controlled?

Write down the reactions involved during the formation of photochemical smog.

Explain tropospheric pollution in 100 words.

What are the reactions involved for ozone layer depletion in the stratosphere?

What would have happened if the greenhouse gases were totally missing in the earth's atmosphere? Discuss.

Statues and monuments in India are affected by acid rain. How?

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

What is smog? How is classical smog different from photochemical smog?

What do you mean by ozone hole? What are its consequences?

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?

Do you expect the carbon hydrides of the type (C_nH_2n+2) to act as 'Lewis' acid or base? Justify your answer.

Out of benzene, m-dinitrobenzene and toluene which will undergo nitration most easily and why?

Use Lewis symbols to show electron transfer between the following atoms to form cations and anions:

(a) K and S (b) Ca and O (c) Al and N.

Chlorine is prepared in the laboratory by treating manganese dioxide (MnO₂) with aqueous hydrochloric acid according to the reaction

4HCl_(aq) + MnO_2(s) → 2H₂O_(l) + MnCl_2(aq) + Cl_2(g)

How many grams of HCl react with 5.0 g of manganese dioxide?

An alkene 'A' on ozonolysis gives a mixture of ethanal and pentan-3-one. Write structure and IUPAC name of 'A'.

Describe the bulk preparation of dihydrogen by electrolytic method. What is the role of an electrolyte in this process?

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

What do you understand by bond pairs and lone pairs of electrons? Illustrate by giving one example of each type.

Predict which of the following reaction will have appreciable concentration of reactants and products:

a) Cl₂ (g)  ↔  2Cl (g)                             Kc = 5 ×10^–39

b) Cl₂ (g) + 2NO (g)  ↔  2NOCl (g)         Kc = 3.7 × 10⁸

c) Cl₂ (g) + 2NO₂ (g)  ↔  2NO₂Cl (g)      Kc = 1.8

Which one of the following will have largest number of atoms?

(i) 1 g Au (s)

(ii) 1 g Na (s)

(iii) 1 g Li (s)

(iv) 1 g of Cl2(g)