Recent questions in Chemistry

Percentage of free space in cubic close packed structure and in body centered packed structure are respectively:

asked Feb 17, 2014 by sharmaaparna1

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By how much is oxidizing power of $MnO_4^-/Mn^{+2}$ couple decreases if the $H^+$ concentration is decreased from 1M to $10^{-4}$M at $25^{\large\circ}C$ .Assume other species have no change in concentration.

asked Feb 17, 2014 by sreemathi.v

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The edge length of a face centered cubic cell of an ionic substance is 508 pm .If the radius of the carbon is 110pm , the radius of the anion is

asked Feb 17, 2014 by sharmaaparna1

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Copper Crystallizes in f.c.c with a unit cell length of 361 pm. What is the radius of copper atom?

asked Feb 17, 2014 by sharmaaparna1

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The EMF of cell $Ag/AgCl(K_{sp})(saturated\; sol)\parallel Cl^-(C_1)/AgCl(K_{sp}/Ag)$ is given by

asked Feb 17, 2014 by sreemathi.v

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In a compound atoms of element Y form ccp lattice and those of element X occupy ${\large\frac{2}{3}}^{rd}$ of tetrahedral voids. The formula of the compound will be

asked Feb 17, 2014 by sharmaaparna1

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How many Faradays are required to reduce on mole of $MnO_4^-$ to $Mn^{+2}$

asked Feb 17, 2014 by sreemathi.v

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Total Volume of atoms present in a face centered cubic unit cell of a metal is (r is atomic radius)

asked Feb 17, 2014 by sharmaaparna1

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The $E_{cell}$ in which the reaction :$MnO_4^-+Fe^{+2}+H^+\rightarrow Mn^{+2}+Fe^{+3}+H_2O$ occurs is 0.59V at $25^{\large\circ}C$.The equilibrium constant for the reaction is

asked Feb 17, 2014 by sreemathi.v

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An ionic compound has unit cell consisting of A ions at the corners of a cube and B ions on the centres of the faces of cube. The empirical formula of this compound is

asked Feb 17, 2014 by sharmaaparna1

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$Zn/Zn^{+2}(C_1)\parallel Zn^{+2}(C_2)/Zn$.For this cell $\Delta G$ is -ve if

asked Feb 17, 2014 by sreemathi.v

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How many unit cells are present in a cubic shaped ideal crystals of NaCl of mass 1.0g?

asked Feb 17, 2014 by sharmaaparna1

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Na and Mg crystallise in b.c.c and f.c.c type crystals respectively , then the number of atoms of Na and Mg present in the unit cell of their respectively crystal is

asked Feb 17, 2014 by sharmaaparna1

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Which of the following facts is not true?

asked Feb 17, 2014 by sreemathi.v

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Sulphur Vapour($S_n$) diffuses through a process plug at 0.354 rate of diffusion of $O_2$ gas under similar conditions of P and T. Find the volume of n.

asked Feb 17, 2014 by sharmaaparna1

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If $E^0_{Fe^{+2}/Fe}$ is $X_1$,$E^0_{Fe^{+3}/Fe}$ is $X_2$ then $E^0_{Fe^{+3}/Fe^{+2}}$ will be

asked Feb 17, 2014 by sreemathi.v

1 answer

A solution containing one mole per litre each of $Cu(NO_3)_2,AgNO_3,Hg_2(NO_3)_2,Mg(NO_3)_2$ is being electrolysed by using inert electrodes.The values of standard potentials are $E^0_{Ag^+/Ag}=0.8V$,$E^0_{Hg^{+2}/Hg}=0.79V$,$E^0_{Cu^{+2}/Cu}=0.34V$,$E^0_{Mg^{+2}/Mg}=-2.3V$ with increasing voltage the sequence of deposition of metals on the cathode will be

asked Feb 17, 2014 by sreemathi.v

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A current of 2A when passed for five hour through a molten metal salt,it deposits 22.2g of metal of atomic weight 177.The oxidation state of metal in metal salt is

asked Feb 17, 2014 by sreemathi.v

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The standard reduction potentials at 298K for following half reaction are given against each.
$Zn^{+2}(aq)+2e^-\leftrightharpoons 2n(s)=-0.762$
$Cr^{+3}(aq)+3e^-\leftrightharpoons Cr(s)=-0.740$
$2H^+(aq)+3e^-\leftrightharpoons H_2(g)=0$
$Fe^{+3}(aq)+e^-\leftrightharpoons Fe^{+2}(aq)=0.770$.

Which is the strongest reducing agent ?

asked Feb 17, 2014 by sreemathi.v

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Four moles of electrons were transferred from anode to cathode in an experiment of electrolysis of water.The total volume of two gases produced will be approximately(in litre) at STP.

asked Feb 17, 2014 by sreemathi.v

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Depression in freezing points of $0.1\;M$ aqueous solution of $HCl,CuSO_4$ and $K_2SO_4$ are

asked Feb 17, 2014 by sreemathi.v

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At 298K temperature ,the Henry constants for $Ar,CO_2,CH_4$ and $O_2$ are 40 kbar,1.6 kbar,0.41 kbar and 34 kbar respectively.Which of the following show maximum solubility in water at a given pressure?

asked Feb 17, 2014 by sreemathi.v

1 answer

Which one of the following aqueous solutions has the lowest vapour pressure?

asked Feb 17, 2014 by sreemathi.v

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The Van't Hoff factor of $Na_2SO_3$ is

asked Feb 17, 2014 by sreemathi.v

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The time for a certain volume of a gas A to diffuse through a small hole is 2 minute. If it takes 5.65 minute for oxygen to diffuse under simililar conditions. Find the molecular weight of A.

asked Feb 16, 2014 by sharmaaparna1

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At same temperature two bulbs A and B of equal capacity are filled with He and $SO_2$ respectively. If the pressure in two bulbs is same. Calculate the ratio of rms speed for them.

asked Feb 16, 2014 by sharmaaparna1

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At 400K the root mean square (rms) speed of a gas x (mol weight = 40) is equal to the most probable speed of gas Y at 60K. Find the molecular weight of gas Y

asked Feb 16, 2014 by sharmaaparna1

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5.6 litre of an unknown gas at NTP requires 12.5 calorie to raise its temperature by $10^{\large\circ}C$ at constant volume. Calculate the $C_v$ of the gas.

asked Feb 16, 2014 by sharmaaparna1

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1 litre capacity flask containing $HN_3$ at 1 atm and $25^{\large\circ}C$. A spark is passed through untill all the $HN_3$ is decomposed into $N_2$ and $H_2$. Calculate the pressure of gases left at $25^{\large\circ}$

asked Feb 16, 2014 by sharmaaparna1

1 answer

Calculate the volume occupied by 96g $CH_4$ at 16 atm and $27^{\large\circ}C$.(R = 0.08litre atm $K^{-1}mol^{-1}$.

asked Feb 16, 2014 by sharmaaparna1

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A container having 3 mole of gas occupies 60 litre at pressure P and temperature T . If 0.2 mole of gas are introduced at same P and T. Find the change in volume.

asked Feb 15, 2014 by sharmaaparna1

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A certain amount of an ideal gas occupies a volume of $1.0m^3$ at a given temperature and pressure. What would be its volume after reducing its pressure to half the initial value and raising the temperature twice the initial value?

asked Feb 15, 2014 by sharmaaparna1

1 answer

4 litre $C_2H_4(g)$ burns in oxygen at $27^{\large\circ}C$ and 1atm to produce $CO_2(g)$and $H_2O(g)$. Calculate the volume of $CO_2$ formed at $27^{\large\circ}C$ and 4 atm

asked Feb 15, 2014 by sharmaaparna1

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7g of a gas occupies a volume of 4:1 litre at 300K. If mol weight of gas is 42 , then find the pressure of it.

asked Feb 15, 2014 by sharmaaparna1

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Calculate the weight of $N_2$ in 6.24 litre cylinder at $27^{\large\circ}C$ and 750 mm Hg. (R = 0.0821 litre atm $K^{-1}mol^{-1}$)

asked Feb 15, 2014 by sharmaaparna1

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A compound exists in the gaseous phase both as monomer (A) and dimer $(A_2)$. The molecular weight of A is 48 . In an experiment 96g of the compound was confined in a vessel of volume 33.6 litre and heated to $273^{\large\circ}C$. Calculate the pressure developed if the compound exists as dimer to the extent of $50\%$ by weight under these conditions.

asked Feb 15, 2014 by sharmaaparna1

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Calculate the pressure exerted by $10^{23}$ gas molecules each of mass $10^{-22}$ g in a container of volume one litre. The rms speed is $10^5 cm \;sec^{-1}$

asked Feb 15, 2014 by sharmaaparna1

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Under 3atm , 12.5 litre of a certain gas weigh 15g. Calculate the average speed of gaseous molecules.

asked Feb 15, 2014 by sharmaaparna1

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A 4:1 molar mixture of He and $CH_4$ is contained in a vessel at 20 bar pressure. Due to a hole in the vessel, the gas mixture leaks out. What is the composition of the mixture effusing out initially?

asked Feb 15, 2014 by sharmaaparna1

1 answer

The relative rates of diffusion of gas B as compared to that of diatomic gas A is 6.5. Find the molecular weight of B if atomic weight of A is 36.

asked Feb 15, 2014 by sharmaaparna1

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How much $CaCO_3$ is present in 100ml of 1000ppm $CaCO_3$ solution?

asked Feb 14, 2014 by sreemathi.v

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1000 mL of aqueous solutions of $CaCO_3$ contains 1 gm of carbonate,concentration of the solution is

asked Feb 14, 2014 by sreemathi.v

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At 293K temperature,the Henry's Law constants for $He,H_2,N_2$ and $O_2$ are 144 kbar,69 kbar,76 kbr and 34.86 kbar respectively. Which of the following show maximum solubility in water at a given pressure

asked Feb 14, 2014 by sreemathi.v

1 answer

For the following disproportion reaction $3Br_2+6OH^{-}\rightarrow 5Br^-+BrO_3^-+3H_2O$. Correct statement below is (Given $Br_2$ molecular mass is 160)

asked Feb 14, 2014 by sreemathi.v

1 answer

Which of the following statements about Raoult's Law is/are correct?

asked Feb 14, 2014 by sreemathi.v

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$PtCl_4.6H_2O$ can exist as a hydrated complex. If 1 molal aqueos solution has a depression in freezing point of $3.72^{\large\circ}$,assuming 100% ionization and $K_f$ of $1.86^{\large\circ}mol^{-1}kg$ which of the following is the complex in question?

asked Feb 14, 2014 by sreemathi.v

1 answer

Relative decrease in vapour pressure of an aqueous glucose dilute solution is found to be 0.018.What is the elevation in boiling point? (Given 1 molal aq.glucose solution boils at 100.62$^{\large\circ}C$ at 1 atm.pressure)

asked Feb 14, 2014 by sreemathi.v

1 answer

12.2gm of benzonic acid (M=122) in 100gm benzene has depression in freezing point $2.6^{\large\circ}C$; $K_f = 5.2 ^{\circ} mol^{-1}kg$. If there is 100% polymerization, the number of molecules of benzonic acid in associated state is

asked Feb 14, 2014 by sreemathi.v

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The van't Hoff factor of $CH_3COOH$ is less than unity. It indicates that the acetic acid

asked Feb 14, 2014 by sreemathi.v

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The 2.56gm of sulphur in 100gm of $CS_2$ has depression in freezing point of $0.010^{\large\circ}$C. $K_f=0.1^{\large\circ}C$/molal. Hence atomicity of sulphur in $CS_2$

asked Feb 14, 2014 by sreemathi.v

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