Recent questions tagged unit4

Hybridisation is defined as the phenomenon of mixing of orbitals of nearly the same energy so as to redistribute their energies and to give rise to new orbitals of equivalent energy. It is the valence shell atomic which get hybridised one of the electrons from an orbital in the ground state electronic configuration of the atom gets promoted to the next available orbital of higher energy resulting in an excited state electronic configuration with the appropriate number of half filled orbitals. The orbitale in the excited state undergo hybridisation giving hybrid orbilats of equivalent energy. Hybrid orbitals generally from either bonds or contain lone pair of electrons, they do not form $\pi$ bonds. Depending on the type of orbitals used the hybridisation may be categorized as $SP$(linear), $SP^2$ (trigonal planar ), $SP^3$(tetrahedral), $SP^3d$(trigonal bipyramidal), $SP^3d^2$(Octahedral), $SP^3d^3$ (Pentagonal bipyramid ). Which one of the following species is diamagnetic ?

asked Apr 3, 2014 by meena.p

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Hydrogen bonding is an electrostatic attraction between covalently bonded hydrogen atom of one molecular with highly electronegative atom (N or F or O) of the same molecular or another molecule. or another molecular .It is of two types -(i) Intermolecular hydrogen bonding where molecular association is caused due to interaction of $H-atom$ of one molecular and N or F or 0-atoms of different molecules. (ii) Intramolecular hydrogen bonding where hydrogen bonding occurs between H atom and N or F or O-atom of the same molecule. Intermolecular hydrogen bonding increases the boiling point of the compound and its solubility in water , whereas intramolecular hydrogen bonding decreases the boiling point of the compound and solubility in water. Which one among the following does not have the hydrogen bond?

asked Apr 2, 2014 by meena.p

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Hydrogen bonding is an electrostatic attraction between covalently bonded hydrogen atom of one molecular with highly electronegative atom (N or F or O) of the same molecular or another molecule. or another molecular .It is of two types -(i) Intermolecular hydrogen bonding where molecular association is caused due to interaction of $H-atom$ of one molecular and N or F or 0-atoms of different molecules. (ii) Intramolecular hydrogen bonding where hydrogen bonding occurs between H atom and N or F or O-atom of the same molecule. Intermolecular hydrogen bonding increases the boiling point of the compound and its solubility in water , whereas intramolecular hydrogen bonding decreases the boiling point of the compound and solubility in water.Highest viscosity is exhibited by

asked Apr 2, 2014 by meena.p

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Hydrogen bonding is an electrostatic attraction between covalently bonded hydrogen atom of one molecular with highly electronegative atom (N or F or O) of the same molecular or another molecule. or another molecular .It is of two types -(i) Intermolecular hydrogen bonding where molecular association is caused due to interaction of $H-atom$ of one molecular and N or F or 0-atoms of different molecules. (ii) Intramolecular hydrogen bonding where hydrogen bonding occurs between H atom and N or F or O-atom of the same molecule. Intermolecular hydrogen bonding increases the boiling point of the compound and its solubility in water , whereas intramolecular hydrogen bonding decreases the boiling point of the compound and solubility in water. The maximum possible number of hydrogen bonds in which a water molecule can participate is

asked Apr 2, 2014 by meena.p

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Hydrogen bonding is an electrostatic attraction between covalently bonded hydrogen atom of one molecular with highly electronegative atom (N or F or O) of the same molecular or another molecule. or another molecular .It is of two types -(i) Intermolecular hydrogen bonding where molecular association is caused due to interaction of $H-atom$ of one molecular and N or F or 0-atoms of different molecules. (ii) Intramolecular hydrogen bonding where hydrogen bonding occurs between H atom and N or F or O-atom of the same molecule. Intermolecular hydrogen bonding increases the boiling point of the compound and its solubility in water , whereas intramolecular hydrogen bonding decreases the boiling point of the compound and solubility in water. The hydrogen bond is strongest in

asked Apr 2, 2014 by meena.p

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The species which contain an odd number of valence electrons and are paramagnetic are

asked Apr 2, 2014 by meena.p

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Intramolecular hydrogen bonds occur is (i) 2- chlorophenol (ii) Salicylic acid (iii) para nitrophenol (iv) none of these

asked Apr 2, 2014 by meena.p

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Which of the following species contain covalent coordinate bonds? $(i)\; AlCl_3 \\ (ii)\;CO \\ (iii)\;[Fe(CN)_6]^{4-} \\ (iv)\; NO_3^{-}$

asked Apr 2, 2014 by meena.p

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Which of the following have identical bond order? $(i)\; CN^{-} \\ (ii)\;NO_2^{-} \\ (iii)\;NO^{+} \\ (iv)\; CN^{+}$

asked Apr 2, 2014 by meena.p

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Which of the following conditions apply to resonating structures? (i) Identical arrangements of atoms (ii) Nearly same energy content (iii) Identical number of bonds (iv) Same number of unpaired electrons

asked Apr 2, 2014 by meena.p

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Which of the following are diamagnetics ? $(i)\;C_2 \\ (ii)\;He_2 \\(iii)\;Li_2 \\(iv)\;N_2 $

asked Apr 2, 2014 by meena.p

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In which of the following the hybrid orbitals of the central atom have the same s-characters ? $(i)\;CH_4 \qquad (ii)\; Ni(CO) \qquad (iii)\;SF_4 \qquad (iv) [Ni(CN)_4]^{2-} $

asked Apr 2, 2014 by meena.p

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Consider the reaction ,$2A +B \to products$ when concentration of B alone was doubled , the half -life did not change . When the concentration of A alone was doubled, the rate increased by two times. The unit of rate constant for this reaction is :

asked Apr 2, 2014 by meena.p

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The time for half life period of a certain reaction. A - products is 1 hour when initial concentration of the reactant A is $2.0\; mol\; L^{-1}$, how much time does it take for its concentration to come from $0.50$ to $ 0.25\;mol L^{-1}$ if it is a zero order reaction ?

asked Apr 2, 2014 by meena.p

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In the following first order reactions : $A+ Regent \quad \underrightarrow{K_1} \quad product; \qquad B+ Reagent \quad \underrightarrow {K_2} \quad Product$ The ratio of $\large\frac{K_1}{K_2}$ when only $50 \%$ of B reacts in a given time when $94 \%$ of a has been reacted is :

asked Apr 2, 2014 by meena.p

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The $ONO$ bond angle is maximum in

asked Apr 2, 2014 by meena.p

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Which of the following are isoelectronic and isostructural ? $NO_3^{-},CO_3^{2-},ClO_3^{-}, SO_3$

asked Apr 2, 2014 by meena.p

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Which is most viscous?

asked Apr 2, 2014 by meena.p

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The electronegativities of $F,Cl,Br$ and $I$ are $4.0,3.0,2.8$ and $2.5$ respectively. Hydrogen halide with a high percentage of ionic character is

asked Apr 2, 2014 by meena.p

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$N_2$ forms $Ncl_3$ whereas P can form both $Pcl_3$ and $PCl_5$ why ?

asked Apr 2, 2014 by meena.p

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In III A group ,Tl (Thalium) shows stable +1 oxidation state, while boron shows stable +3 oxidation state. It is due to

asked Apr 2, 2014 by meena.p

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Which one of the following oxides is expected to exhibit paramagnetic behaviour ?

asked Apr 2, 2014 by meena.p

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Which of the species is diamagnetic ?

asked Apr 2, 2014 by meena.p

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Correct order of bond length is

asked Apr 1, 2014 by meena.p

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The statement true for $N_3 ^{-}$ is :

asked Apr 1, 2014 by meena.p

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In piperidine N-atom has hybridisation

asked Apr 1, 2014 by meena.p

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Correct order of dipole moment for the following molecules is

asked Apr 1, 2014 by meena.p

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Among the following compounds the one that is polar and has the central atom with $SP^2$ hybridisation is :

asked Apr 1, 2014 by meena.p

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The cyanide ion, $CN^{-}$ and $N_2$ are isoelectronic . But in contrast to $CN^{-},N_2$ is chemically inert, because of

asked Apr 1, 2014 by meena.p

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During the formation of a molecular orbital from atomic orbitals , the electron density is

asked Apr 1, 2014 by meena.p

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Which of the following molecular is the most polar?

asked Apr 1, 2014 by meena.p

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Arrange the following compounds in order of increasing dipole moment? (I) Toluene (II) m-dichlorobenzene (III) o-dichlorobenzene (IV) P-dichlorobenzene

asked Apr 1, 2014 by meena.p

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The hybridisation of atomic orbitals of nitrogen in $NO_2^{+},NO_3^{-}$ and $NH_4^{+}$ are

asked Apr 1, 2014 by meena.p

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