How can the production of dihydrogen, obtained from ‘coal gasification’, be increased?
Dihydrogenis produced by coal gasification method as:
C(s) + H2O(g) → CO(g) + H2(g)
The yield of dihydrogen (obtained from coal gasification) can be increased by reacting carbon monoxide (formed during the reaction) with steam in the presence of iron chromate as a catalyst.
This reaction is called the water-gas shift reaction. Carbon dioxide is removed by scrubbing it with a solution of sodium arsenite.
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.
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.
Discuss the principle and method of softening of hard water by synthetic ion-exchange resins.
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?
What do you understand by bond pairs and lone pairs of electrons? Illustrate by giving one example of each type.
What would have happened if the greenhouse gases were totally missing in the earth's atmosphere? Discuss.
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)
Kp = 0.04 atm at 899 K for the equilibrium shown below. What is the equilibrium concentration of C2H6 when it is placed in a flask at 4.0 atm pressure and allowed to come to equilibrium?
C2H6 (g) ↔ C2H4 (g) + H2 (g)
Use the data given in the following table to calculate the molar mass of naturally occurring argon isotopes:
Isotope |
Isotopic molar mass |
Abundance |
36Ar |
35.96755 gmol–1 |
0.337% |
38Ar |
37.96272 gmol–1 |
0.063% |
40Ar |
39.9624 gmol–1 |
99.600% |
Compare the relative stability of the following species and indicate their magnetic properties:
O2,O2+,O2- (superoxide), O22-(peroxide)
What is the minimum volume of water required to dissolve 1g of calcium sulphate at 298 K? (For calcium sulphate, Ksp is 9.1 x 10-6).
(a) How many sub-shells are associated with n = 4?
(b) How many electrons will be present in the sub-shells having ms value of –1/2 for n = 4?
A 0.02 M solution of pyridinium hydrochloride has pH = 3.44. Calculate the ionization constant of pyridine