Draw the Lewis structures for the following molecules and ions: H2S, SiCl4, BeF2, , HCOOH
1) H2S H has 1 electron in its valence shell & sulphur has 6 electron its valence shell. A planar structure will be formed
2) Si has 4 electrons its valence shell & Cl need only 1 electron to complete its octet, therefore 4 Cl will make 4 bonds with Si.A tetrahedral shape will be formed
3) Be has 2 electrons in its valence shell & Fe has 2 electrons in its valence shell, so they make a planar structure
4) here C has 4 electron its valence shell, therefore it can make 4 bond with other atoms, whereas O has 6 electrons in its valence shell, it can accept 2 electron easily to complete its octet, therefore one O will make a double bond with C , while other two O will make 2 single bond with C.
5) HCOOH- C has 4 electron its valence shell, therefore it can make 4 bond with other atoms, whereas O has 6 electrons in its valence shell, it can accept 2 electron easily to complete its octet,
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–
Which hybrid orbitals are used by carbon atoms in the following molecules?
(a)CH3–CH3;
(b) CH3–CH=CH2;
(c) CH3-CH2-OH;
(d) CH3-CHO
(e) CH3COOH
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.
What happens when
(i) sodium metal is dropped in water ?
(ii) sodium metal is heated in free supply of air ?
(iii) sodium peroxide dissolves in water ?
The enthalpies of all elements in their standard states are:
(i) unity
(ii) zero
(iii) < 0
(iv) different for each element
How does the atomic hydrogen or oxy-hydrogen torch function for cutting and welding purposes? Explain.
Explain, giving reasons, which of the following sets of quantum numbers are not possible.
a n = 0 l = 0 ml = 0
b n = 1 l = 0 ml = 0
c n = 1 l = 1 ml = 0
d n = 2 l = 1 ml = 0
e n = 3 l = 3 ml = – 3
f n = 3 l = 1 ml = 0
At 450K, Kp= 2.0 × 1010/bar for the given reaction at equilibrium.
2SO2(g) + O2(g) ↔ 2SO3 (g)
What is Kc at this temperature ?
Arrange the following type of radiations in increasing order of frequency:
(a) radiation from microwave oven
(b) amber light from traffic signal
(c) radiation from FM radio
(d) cosmic rays from outer space and
(e) X-rays.
Describe the effect of :
a) addition of H2
b) addition of CH3OH
c) removal of CO
d) removal of CH3OH on the equilibrium of the reaction: 2H2(g) + CO (g) ↔ CH3OH (g)
Determine the empirical formula of an oxide of iron which has 69.9% iron and 30.1% dioxygen by mass.
Discuss the various reactions that occur in the Solvay process.
Identify the reagents shown in bold in the following equations as nucleophiles or electrophiles:
(a) CH3COOH + HO- → CH3COO- + H2O
(b) CH3COCH3 + C-N → (CH3)2 C (CN) (OH)
(c) C6H5 + CH3C+O → C6H5COCH3
Thanks