Consider the reaction of water with F2 and suggest, in terms of oxidation and reduction, which species are oxidised or reduced.
The reaction between fluorine and water can be represented as:
2F2(g) + 2H2O(I) → 4H+(aq) + 4F-(aq) + O2(g)
This is an example of a redox reaction as water is getting oxidized to oxygen, while fluorine is being reduced to fluoride ion.
The oxidation numbers of various species can be represented as:
Fluorine is reduced from zero to (-1) oxidation state. A decrease in oxidation state indicates the reduction of fluorine. Water is oxidized from (-2) to zero oxidation state. An increase in oxidation state indicates oxidation of water.
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?
Explain why alkali and alkaline earth metals cannot be obtained by chemical reduction methods?
Why does benzene undergo electrophilic substitution reactions easily and nucleophilic substitutions with difficulty?
What will be the pressure exerted by a mixture of 3.2 g of methane and 4.4 g of carbon dioxide contained in a 9 dm3 flask at 27 °C ?
Why does the following reaction occur ?
XeO4– 6(aq) + 2F – (aq) + 6H + (aq) → XeO3(g) + F2(g) + 3H2O(l)
What conclusion about the compound Na4XeO6 (of which XeO4– 6 is a part) can be drawn from the reaction.
The ejection of the photoelectron from the silver metal in the photoelectric effect experiment can be stopped by applying the voltage of 0.35 V when the radiation 256.7 nm is used. Calculate the work function for silver metal.
Discuss the pattern of variation in the oxidation states of
(i) B to Tl and (ii) C to Pb.
What is the maximum number of emission lines when the excited electron of an H atom in n = 6 drops to the ground state?
The velocity associated with a proton moving in a potential difference of 1000 V is 4.37 × 105 ms–1. If the hockey ball of mass 0.1 kg is moving with this velocity, calculate the wavelength associated with this velocity.
Statues and monuments in India are affected by acid rain. How?
How would you explain the fact that the first ionization enthalpy of sodium is lower than that of magnesium but its second ionization enthalpy is higher than that of magnesium?