Recent questions tagged 2003

What would happen when a solution of potassium chromate is treated with an excess of dilute nitric acid ?

asked Dec 11, 2018 by pady_1

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The number of d-electrons retained in $Fe^{2+}$ (At. no. Fe = 26) ions is :

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The substance used in Holmes signals of the ship is a mixture of :

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Concentrated hydrochloric acid when kept in open air sometimes produces a cloud of white fumes. The explanation for it is that :

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A red solid is insoluble in water. However it becomes soluble if some $KI$ is added to water. Heating the red solid in a test tube results in liberation of some violet coloured fumes and droplets of metal appear on the cooler parts of the test tube. The red solid is :

asked Dec 11, 2018 by pady_1

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Which one of the following is an atmospheric oxide ?

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Which one of the following substances has the highest proton affinity ?

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Standard reduction electrode potentials of three metals $A, \;B$ and $C$ are $+0.5 V, \; -3.0 V$ and $-1.2V$ respectively. The reducing power of these metals are:

asked Dec 11, 2018 by pady_1

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In the respect of the equation $k = Ae^{-E_a/RT}$ in chemical kinetics, which one of the following statement is correct ?

asked Dec 11, 2018 by pady_1

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Which one of the following characteristics is not correct for physical adsorption ?

asked Dec 11, 2018 by pady_1

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In an irreversible process taking place at constant T and P and in which only pressure-volume work is being done, the change in Gibbs free energy (dG) and change in entropy (dS), satisfy the criteria :

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For a cell reaction involving a two-electron change, the standard emf of the cell is found to be 0.295 V at $25^{\circ}$. The equilibrium constant of the reaction at $25^{\circ}C$ will be :

asked Dec 11, 2018 by pady_1

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For the reaction system : $2NO(g) + O_2(g) \to 2NO_2 (g)$ volume is suddenly reduced to half its value by increasing the pressure on it. If the reaction is of first order with respect to $O_2$ and second order with respect to NO; the rate of reaction will :

asked Dec 11, 2018 by pady_1

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If liquids A and B form an ideal solution, the :

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A pressure cooker reduces cooking time for food because :

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The enthalpy change for a reaction does not depend upon the :

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If at 298 K the bond energies of $C-H$, $C-C$, $C=C$ and $H-H$ bonds are respectively $414, \; 347, \; 615$ and $435 \; k \; J \; mol^{-1}$, the value of enthalpy change for the reaction $H_2C = CH_2(g) + H_2(g) \to H_3C - CH_3 (g)$ at 298 K will be :

asked Dec 11, 2018 by pady_1

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The correct relationship between free energy change in a reaction and the corresponding equilibrium constant $K_c$ is :

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25 mL of a solution of barium hydroxide on titration with 0.1 molar solution of hydrochloric acid gave a titre value of 35 mL. The molarity of barium hydroxide solution was :

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The rate law for a reaction between the substances A and B is given by rate = $k [A]^n [B]^m$. On doubling the concentration of A and halving the concentration of B, the ratio of the new rate to the earlier rate of the reaction will be as:

asked Dec 11, 2018 by pady_1

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In a 0.2 molal aqueous solution of a weak acid HX, the degree of ionisation is 0.3. Taking $K_f$ for water as $1.85$, the freezing point of the solution will be nearest to :

asked Dec 11, 2018 by pady_1

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For the redox reaction $Zn(s) + Cu^{2+} (0.1 M) \to Zn^{2+} (1M) + Cu(s) $ taking place in a cell, $E^{\circ}_{cell}$ is $1.10\; volt$. $E_{cell}$ for the cell will be : $(2.303 \frac{RT}{F}= 0.0591 )$

asked Dec 11, 2018 by pady_1

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When during electrolysis of a solution of $AgNO_3, $ 9650 coulombs of charge pass through the electroplating bath, the mass of silver deposited on the cathode will be :

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The solubility in water of a sparingly soluble salt $AB_2$ is $1.0 \times 10^{-5} mol\;L^{-1}$. Its solubility product number will be :

asked Dec 11, 2018 by pady_1

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For the reaction equilibrium, $N_2O_4 (g) \rightleftharpoons 2 NO(g)$ the concentrations of $N_2O_4$ and $NO_2$ at equilibrium are $4.8 \times 10^{-2}$ and $1.2 \times 10^{-2} mol L^{-1}$ respectively. The value of $K_c$ for the reaction is :

asked Dec 11, 2018 by pady_1

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What volume of hydrogen gas, at 273 K and 1 atm pressure will be consumed in obtaining 21.6 g of elemental boron (atomic mass = 10.8) from the reduction of boron trichloride by hydrogen ?

asked Dec 11, 2018 by pady_1

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Consider the reaction equilibrium : $2SO_2(g) + O_2(g) \rightleftharpoons 2SO_3 (g); \; \; \; \Delta H^{\circ} = -198 kJ$ On the basis of Le-Chatelier's principle, the condition favourable for the forward reaction is :

asked Dec 11, 2018 by pady_1

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The atomic numbers of vanadium (V), chromium (Cr), manganese (Mn) and iron (Fe) are respectively 23, 24, 25 and 26. Which one of these may be expected to have the highest second ionization enthalpy ?

asked Dec 11, 2018 by pady_1

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The pair of species having identical shapes for molecules of both species is :

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In the anion $HCOO^-$ the two carbon-oxygen bonds are found to be of equal length. What is the reason for it ?

asked Dec 11, 2018 by pady_1

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Which one of the following groupings represents a collection of isoelectronic species ? (At. numbers : Cs - 55, Br - 35)

asked Dec 11, 2018 by pady_1

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Which one of the following pairs of molecules will have permanent dipole moments for both members ?

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Which one of the following compounds has the smallest bond angle in its molecule ?

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Which one of the following processes will produce hard water ?

asked Dec 11, 2018 by pady_1

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Among the following four structures $I$ to $IV$ : it is true that :

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An ether is more volatile than an alcohol having the same molecular formula. This is due to :

asked Dec 11, 2018 by pady_1

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The general formula $C_n H_{2n} O_2$ could be for open chain :

asked Dec 11, 2018 by pady_1

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Which of the following group of transition metals is called coinage metals ?

asked Dec 11, 2018 by pady_1

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According to the kinetic theory of gases, in an ideal gas, between two successive collisions a gas molecule travels :

asked Dec 11, 2018 by pady_1

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When $CH_2 = CH - COOH$ is reduced with $LiAlH_4$, the compound obtained will be :

asked Dec 11, 2018 by pady_1

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The IUPAC name of $CH_3COCH(CH_3)_2$ is :

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Graphite is a soft solid lubricant extremely difficult to melt. The reason for this anomalous behaviour is that graphite :

asked Dec 11, 2018 by pady_1

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According to the periodic law of elements, the variation in properties of elements is related to their :

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Which one of the following statements is correct ?

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Glass is a :

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How many unit cells are present in a cube shaped ideal crystal of $NaCl$ of mass $1.00\;g$ ? [Atomic masses : Na = 23, Cl = 35.5]

asked Dec 11, 2018 by pady_1

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The orbital angular momentum for an electron revolving in an orbit is given by $\sqrt{l(l+1)} \frac{h}{2 \pi} $. The momentum for an s-electron will be given by :

asked Dec 11, 2018 by pady_1

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The de-Broglie wavelength of a tennis ball of mass 60 g moving with a velocity of 10 m/s is approximately : (Plancks constant, $h =6.63 \times 10^{-34} Js$)

asked Dec 11, 2018 by pady_1

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In Bohr series of lines of hydrogen spectrum, the third line from the red end corresponds to which one of the following inner-orbit jumps of the electron for Bohr orbits in an atom of hydrogen ?

asked Dec 11, 2018 by pady_1

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The length of a given cylindrical wire is increased by 100%. Due to the consequent decrease in diameter the change in the resistance of the wire will be :

asked Dec 11, 2018 by pady_1

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