Compare the relative stability of the following species and indicate their magnetic properties:
O2,O2+,O2- (superoxide), O22-(peroxide)
The stability of following species can be decided on the basis of bond order as follows:
O2 : KK
Bond order =1/2(Nb-Na)
= 1/2(8-4)
= 2 = Paramagnetic
Similarly, the electronic configuration of O2+ can be written as:
Bond order of O2+ = 1/2(8-3)
= 2.5 = paramagnetic
Electronic configuration of O2- ion will be:
Bond order of = 1/2(8-5)
= 1.5 = paramagnetic
Electronic configuration of O22- ion will be:
Bond order of O22- =1/2(8-6) = 1 diamagnetic
The larger the bond order,greater is the stability
Therefore the stability decreases as O2+ > O2 > O2- > O22-.
What is meant by the term bond order? Calculate the bond order of: N2, O2,O2+,and O2-.
Use molecular orbital theory to explain why the Be2 molecule does not exist.
Explain the formation of H2 molecule on the basis of valence bond theory.
Describe the hybridisation in case of PCl5. Why are the axial bonds longer as compared to equatorial bonds?
Which out of NH3 and NF3 has higher dipole moment and why?
Explain why BeH2 molecule has a zero dipole moment although the Be–H bonds are polar.
Discuss the shape of the following molecules using the VSEPR model:
BeCl2, BCl3, SiCl4, AsF5, H2S, PH3
Write Lewis symbols for the following atoms and ions:
S and S2–; Al and Al3+; H and H–
Draw the Lewis structures for the following molecules and ions: H2S, SiCl4, BeF2, , HCOOH
Describe the change in hybridisation (if any) of the Al atom in the following reaction.
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?
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?
Justify the position of hydrogen in the periodic table on the basis of its electronic configuration.
Given the standard electrode potentials,
K+/K = -2.93V, Ag+/Ag = 0.80V,
Hg2+/ Hg = 0.79V
Mg2+/ Mg = -2.37V. Cr3+/ Cr = -0.74V
Arrange these metals in their increasing order of reducing power.
The species: H2O, HCO–3, HSO-4 and NH3 can act both as Brönsted acids and bases. For each case give the corresponding conjugate acid and base.
Give one method for industrial preparation and one for laboratory preparation of CO and CO2 each.
What happens when
(i) magnesium is burnt in air
(ii) quick lime is heated with silica
(iii) chlorine reacts with slaked lime
(iv) calcium nitrate is heated ?
Compare the solubility and thermal stability of the following compounds of the alkali metals with those of the alkaline earth metals.
(a) Nitrates (b) Carbonates (c) Sulphates.
An ion with mass number 37 possesses one unit of negative charge. If the ion contains 11.1% more neutrons than the electrons, find the symbol of the ion.
Calculate the temperature of 4.0 mol of a gas occupying 5 dm3 at 3.32 bar.
(R = 0.083 bar dm3 K–1 mol–1).
Enthalpy of combustion of carbon to CO2 is -393.5 kJ mol-1. Calculate the heat released upon formation of 35.2 g of CO2 from carbon and dioxygen gas.
Do you expect the carbon hydrides of the type (CnH2n+2) to act as 'Lewis' acid or base? Justify your answer.
Explain tropospheric pollution in 100 words.
Whats KK ?
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How to identify para or dia magnet ic
WASTE
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