Explain with the help of suitable example polar covalent bond.
If two different atoms are linked to each other by covalent bond, then the shared electron pair will not lie in the centre because the bonding atoms differ in electro-negativities. Such a bond is called as polar covalent bond. In NaCl, chlorine is more electronegative than sodium. Hence it will have more control over the shared pair of electrons and will develops a partial negative charge and sodium will acquire partial positive charge and a polar covalent bond is formed. Greater the difference in electronegativity of bonding atoms, more will be the polarity of the bond.
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.
Compare the relative stability of the following species and indicate their magnetic properties:
O2,O2+,O2- (superoxide), O22-(peroxide)
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–
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.
Calculate a) ΔG0 and b) the equilibrium constant for the formation of NO2 from NO and O2 at 298K
NO (g) + ½ O2 (g) ↔ NO2 (g)
where ΔfG0 (NO2) = 52.0 kJ/mol
ΔfG0 (NO) = 87.0 kJ/mol
ΔfG0 (O2) = 0 kJ/mol
Write IUPAC names of the products obtained by the ozonolysis of the following compounds:
(i) Pent-2-ene
(ii) 3,4-Dimethyl-hept-3-ene
(iii) 2-Ethylbut-1-ene
(iv) 1-Phenylbut-1-ene
The pH of milk, black coffee, tomato juice, lemon juice and egg white are 6.8, 5.0, 4.2, 2.2 and 7.8 respectively. Calculate corresponding hydrogen ion concentration in each.
What would be the SI unit for the quantity pV2T 2/n?
An atom of an element contains 29 electrons and 35 neutrons.
Deduce (i) the number of protons and (ii) the electronic configuration of the element.
Write the formulae for the following compounds:
(a) Mercury(II) chloride
(b) Nickel(II) sulphate
(c) Tin(IV) oxide
(d) Thallium(I) sulphate
(e) Iron(III) sulphate
(f) Chromium(III) oxide
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.
Define environmental chemistry.
What are the necessary conditions for any system to be aromatic?
Which of the following represents the correct IUPAC name for the compounds concerned?
(a) 2,2-Dimethylpentane or 2-Dimethylpentane
(b) 2,4,7-Trimethyloctane or 2,5,7-Trimethyloctane
(c) 2-Chloro-4-methylpentane or 4-Chloro-2-methylpentane
(d) But-3-yn-1-ol or But-4-ol-1-yne
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The bond in NaCl is Ionic bond not covalent bond hence example is wrong answer is okay
Thanks.... great answer...short,crisp and to the point
Good
Very useful niceeee
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