Define environmental chemistry.
The branch of science which deals with the chemical changes in the environment is called as Environmental Chemistry. It includes our surroundings such as air, water, soil, forests, sunlight etc. It has three main components:
Abiotic or non -living - it includes lithosphere, hydrosphere, atmosphere.
Biotic or living- it includes plant and animal kingdom including humans.
Energy component- it includes solar energy, geochemical, thermochemical, hydroelectric and nuclear energy.
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?
Draw the cis and trans structures of hex-2-ene. Which isomer will have higher b.p. and why?
Explain why cations are smaller and anions larger in radii than their parent atoms?
Among the second period elements the actual ionization enthalpies are in the order
Li < B < Be < C < O < N < F < Ne.
Explain why
(i) Be has higher ΔiH than B
(ii) O has lower ΔiH than N and F?
Write the names of isotopes of hydrogen. What is the mass ratio of these isotopes?
Considering x-axis as the internuclear axis which out of the following will not form a sigma bond and why?
(a) 1s and 1s
(b) 1s and 2px
(c) 2py and 2py
(d) 1s and 2s.
Why are lithium salts commonly hydrated and those of the other alkali metal ions usually anhydrous?
Calculate the wavelength for the emission transition if it starts from the orbit having radius 1.3225 nm and ends at 211.6 pm. Name the series to which this transition belongs and the region of the spectrum.
Anything that influences the valence electrons will affect the chemistry of the element. Which one of the following factors does not affect the valence shell?
(a) Valence principal quantum number (n)
(b) Nuclear charge (Z)
(c) Nuclear mass
(d) Number of core electrons.
Describe the bulk preparation of dihydrogen by electrolytic method. What is the role of an electrolyte in this process?
The hydroxides and carbonates of sodium and potassium are easily soluble in water while the corresponding salts of magnesium and calcium are sparingly soluble in water. Explain.