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Ionisation energy of He+ is 19.6 × 10-18 J atom-1. The energy of the first stationary state (n = 1) of Li2+ is

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DIRECTIONS: These are Assertion-Reason type questions. Question contains two statements:Statement-1 (Assertion) and Statement-2 (Reason). Answer these questions from the following four options.

Statement-1 :Electrical conductivity of semiconductors increases with increasing temperature.
Statement-2 :With increase in temperature, large number of electrons from the valence band can jump to the conduction band.

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    In case of semiconductors, the gap between valence band and the conduction band is small and therefore some of the electrons may jump from valence band to conduction band and thus on increasing temperature conductivity is also increased.

Which substance serves as reducing agent in the following reaction ?

14H+ + \(Cr_{2}O_{7}^{2-}\) + 3Ni ⟶ 2Cr3+ + 7H2O + 3Ni2+

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    The compound undergo oxidation itself and reduces others is known as reducing agent. In this reaction O.N. of Ni changes from 0 to + 2 and hence Ni acts as a reducing agent.

The five d-orbitals are designated as dxy, dyz, dxz, dx2 – y2 and dz2. Choose the correct statement.

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    First four orbitals contain four lobes, while fifth orbital consists of only two lobes. The lobes of dxy orbital lie between x and y axis. Similarly in the case of dyz and dzx. their lobes lie between yz and zx axis respectively. Four lobes of dx2 - y2 orbital are lying along x and y axis while two lobes of dz2 orbital are lying along z-axis.

Which will undergo SN2 reaction fastest among the following halogen compounds?

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    Smaller the R group reactivity will be higher towards SN2 reaction.For alkyl halides containing similar alkyl group better will be the leaving group, more facile is the nucleophilic substitution reaction.

    Amongst the halide ions, the order in which the leaving groups depart follows the sequence :

    I– > Br– > Cl– > F–

    It is because of this reason that the order of reactivity of haloalkanes follows the sequence:

    iodoalkanes > bromoalkanes> chloroalkanes > fluoroalkanes

If the concentration of OH–ions in the reaction Fe(OH)3(s) ⇌ Fe3+(aq) + 3OH–(aq) is decreased by 14 times, then equilibrium concentration of Fe3+ will increase by :

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Which of the following sets of quantum numbers represents the highest energy of an atom?

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    (a) n = 3, l = 0 means 3s-orbital and n + l = 3
    (b) n = 3, l = 1 means 3p-orbital n + l = 4
    (c) n = 3, l = 2 means 3d-orbital n + l = 5
    (d) n = 4, l = 0 means 4s-orbital n + l = 4

    Increasing order of energy among these orbitals is 3s < 3p < 4s < 3d ∴ 3d has highest energy.

The charge on colloidal particles is due to

DIRECTIONS: Read the passage given below and answer the questions that follow :
In hexagonal systems of crystals, a frequently encountered arrangement of atoms is described as a hexagonal prism. Here, the top and bottom of the cell are regular hexagons and three atoms are sandwiched in between them. A space-filling model of this structure, called hexagonal close-packed (hcp), is constituted of a sphereona flat surface surrounded in the same plane by six identical spheres as closely as possible. These spheres are then placed over the first layer so that they touch each other and represent the second layer. Each one of these three spheres touches three spheres of the bottom layer. Finally, the second layer is covered with third layer that is identical to the bottom layer in relative position. Assume radius of every sphere to be ‘r’.28.

The number of atoms in the hcp unit cell is

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[Cr(H2O)6]Cl3(at.no. of Cr = 24) has a magnetic moment of 3.83 B. M. The correct distribution of 3d electrons in the Chromium of the complex is

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One mole of CH3COOH and one mole of C2H5OH reacts to produce 2⁄3 mol of CH3COOC2H5. The equilibrium constant is :

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    CH3COOH + C2H5OH→CH3COOC2H5 + H2O

    At equb. 1-2⁄3 1-2⁄3 2⁄3 2⁄3

    Let the total volume = V L

    ∴[CH3OOH]=1⁄3 V mol/L

    [C2H5OH ] =1⁄3 V mol/L

    [CH3COOC2H5] =2⁄3 V mol/L

    [H2O] =2⁄3 V mol/L

    \(∴K=\frac{\frac{2}{3}V\times \frac{2}{3}V}{\frac{1}{3}V\times \frac{1}{3}V}=4\)

Eutrophication causes reduction in

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    Eutrophication causes reduction in D.O.

Both [Ni(CO)4] and [Ni(CN)4]2- are diamagnetic. Thehy bridisations of nickel in these complexes, respectively,are

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A mixture of two gases A and B in the mole ratio 2 : 3 is kept in a 2 litre vessel. A second 3L vessel has the same two gases in the mole ratio 3 : 5. Both gas mixtures have the same temperature and same total pressure. They are allowed to inter-mix and the final temperature and the total pressure are the same as the initial values, the final volume being 5 litres. Given that the molar masses are MA and MB. What is the mean molar mass of the final mixture?

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Select the process that does not add particulate materials to air.

The product obtained by the reaction of an aldehyde and hydroxylamine is

Which method can be used to distinguish [Co(NH2)6][Cr(NO2)6] and [Cr(NH3)6][Co(NO2)6]

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    In one case, on electrolysis of aqueous solution, the complex ion of cobalt [i.e.,{Co(NH3)6}3+] of the complex[Co(NH3)6][Cr(NO2)6] moves towards cathode(i.e.,negative electrode) and on this electrode finally cobalt would be deposited.

    In another case, on electrolysis of aqueous solution,the complex ion of chromium[i.e., {Cr(NH3)6}3+] of the complex[Cr(NH3)6][Co(NO2)6] moves towards cathode(i.e.,negative electrode) and on this electrode chromium would finally be deposited.

In the reaction CH3 = C– – Na+ + (CH3)2CH -Cl?
The product formed is :

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