Describe the change in hybridisation (if any) of the Al atom in the following reaction.
Here in the given equation AlCl3 , Al is shifting its hybridization state from sp2 to sp3 because if we see the electronic configuration of Al it is [Ne] 3s2 3p1, i.e it has 3 electrons in its valence shell during ground state.In its excited state its one s orbital & two p orbitals will take part in hybridization to form sp2 hybrid orbital.
The orbital picture of aluminium in the excited state can be represented as:
Now according to the given reaction the product formed AlCl4- , will only be formed if its 3pz orbital is also filled by one electron in its excited state to form a sp3 hybrid orbital .therefore Al will shift its hybridization form sp2 to sp3 to form a tetrahedral shape
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?
Discuss the shape of the following molecules using the VSEPR model:
BeCl2, BCl3, SiCl4, AsF5, H2S, PH3
Explain why BeH2 molecule has a zero dipole moment although the Be–H bonds are polar.
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
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 is the wavelength of light emitted when the electron in a hydrogen atom undergoes transition from an energy level with n = 4 to an energy level with n = 2?
Electrons are emitted with zero velocity from a metal surface when it is exposed to radiation of wavelength 6800 Å. Calculate threshold frequency (v0) and work function (W0) of the metal.
Why are potassium and cesium, rather than lithium used in photoelectric cells?
(i) Calculate the number of electrons which will together weigh one gram.
(ii) Calculate the mass and charge of one mole of electrons.
A 25 watt bulb emits monochromatic yellow light of wavelength of 0.57μm. Calculate the rate of emission of quanta per second.
A photon of wavelength 4 × 10–7 m strikes on metal surface, the work function of the metal being 2.13 eV. Calculate
(i) the energy of the photon (eV),
(ii) the kinetic energy of the emission, and
(iii) the velocity of the photoelectron (1 eV= 1.6020 × 10–19 J).
What are pesticides and herbicides? Explain giving examples.
Write the expression for the equilibrium constant, Kc for each of the following reactions:
(i) 2NOCl (g) ↔ 2NO (g) + Cl2 (g)
(ii) 2Cu(NO3)2 (s) ↔ 2CuO (s) + 4NO2 (g) + O2 (g)
(iii) CH3COOC2H5(aq) + H2O(l) ↔ CH3COOH (aq) + C2H5OH (aq)
(iv) Fe3+ (aq) + 3OH– (aq) ↔ Fe(OH)3 (s)
(v) I2 (s) + 5F2 ↔ 2IF5
Which one of the following alkali metals gives hydrated salts?
(a) Li (b) Na (c) K (d) Cs
The work function for caesium atom is 1.9 eV. Calculate
(a) the threshold wavelength and
(b) the threshold frequency of the radiation. If the caesium element is irradiated with a wavelength 500 nm, calculate the kinetic energy and the velocity of the ejected photoelectron.
1/2(3+4+1)=4=sp3
How can you find the hybridisation of alcl4- by using the shortcut formula? 1/2(v+M-c+A)= 1/2(3+4-1) =3=sp2 hybridisation?
Change
So what is the final answer. .Change or no change