Recent questions tagged chemistry

Which one of the following oxides is reduced by water gas to obtain the metal during its extraction ?

asked Nov 9, 2013 by thanvigandhi_1

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Identify the order in which the spin only magnetic moment ( in BM) increases for the following four ions :

asked Nov 9, 2013 by thanvigandhi_1

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The hybridization of Xe and the number of lone pairs of electrons on it in $XeF_6$ are :

asked Nov 9, 2013 by thanvigandhi_1

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What is the bond angle $(\hat{OCIO})$ in $CIO_2$?

asked Nov 9, 2013 by thanvigandhi_1

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What are the products formed when moist chlorine gas is reacted with hypo?

asked Nov 9, 2013 by thanvigandhi_1

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The total number of $ \sigma\: and \: \pi$ bonds in pyrophosphoric acid are respectively :

asked Nov 9, 2013 by thanvigandhi_1

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Which one of the following is a correct set?

asked Nov 9, 2013 by thanvigandhi_1

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Which one of the following statement is not correct?

asked Nov 9, 2013 by thanvigandhi_1

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In which of the following reactions hydrogen is not liberated?

asked Nov 9, 2013 by thanvigandhi_1

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Which property among the following is same for both hydrogen and deuterium molecules?

asked Nov 9, 2013 by thanvigandhi_1

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Which one of the following gives a straight line for Freundlich adsorption isotherm?

asked Nov 9, 2013 by thanvigandhi_1

1 answer

What is the entropy change in $ J.K^{-1}$ during the melting of 27.3 grams of ice at $ 0^{\circ}C$ ? (Latent heat of fusion of ice = 330 $ j.g^{-1}$)

asked Nov 9, 2013 by thanvigandhi_1

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The pH of 0.05 M acetic acid is $ ( K_a = 2 \times 10^{-5} )$

asked Nov 9, 2013 by thanvigandhi_1

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If the equilibrium constant for the reaction $ 2AB \rightleftharpoons A_2+B_2 \: is \: 49$, what is the equilibrium constant for $ AB \rightleftharpoons \large\frac{1}{2}\: A_2 + \large\frac{1}{2}B_2$?

asked Nov 9, 2013 by thanvigandhi_1

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The vapour pressure of water at $23^{\circ}$ is $19.8\;mm. 0.1$ mole of glucose is dissolved in $178.2\;g$ of water. What is the vapour pressure (in mm) of the resultant solution ?

asked Nov 8, 2013 by meena.p

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A and B are ideal gases. The molecular weights of A and B are in the ratio of 1:4 . The pressure of a gas mixture containing equal weights of A and B is P atm. What is the partial pressure (in atm) of B in the mixture ?

asked Nov 8, 2013 by meena.p

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In the reaction

asked Nov 8, 2013 by meena.p

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x grams of calcium carbonate was completely burnt in air. The weight of the solid residue formed is 28 g. What is the value of x (in grams)?

asked Nov 8, 2013 by meena.p

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Which of the following is correct ?

asked Nov 8, 2013 by meena.p

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'Natalite' is used as:

asked Nov 8, 2013 by meena.p

1 answer

Which of the following is a linear molecule ?

asked Nov 8, 2013 by meena.p

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Identify the correct order in which the covalent radius of the following elements increases:

asked Nov 8, 2013 by meena.p

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3-hydroxybutanal is formed when (X) reacts with (Y) in dilute (Z) solution. What are X,Y and Z?

asked Nov 8, 2013 by meena.p

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The half-lives of two radioactive nuclides A and B are taken separately and allowed to disintegrate for 4 min. What will be the ratio of weights of A and B disintegrated?

asked Nov 8, 2013 by meena.p

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An electron is moving in Bohr's fourth orbit. It's de-Broglie wave length is $\lambda$. What is the circumference of the fourth orbit ?

asked Nov 8, 2013 by meena.p

2 answers

Which of the following , compounds is the reactant in Rosenmund's reduction?

asked Nov 8, 2013 by meena.p

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The atomic numbers of elements X,Y and Z are 19,21 and 25 respectively. The number of electrons present in the M shell of these elements follow the order:

asked Nov 8, 2013 by meena.p

1 answer

In which of the following reactions the product is an ether ?

asked Nov 8, 2013 by meena.p

1 answer

Which of the following is an example for heterogeneous catalysis reaction?

asked Nov 8, 2013 by meena.p

1 answer

Which one of the following reactions does not form gaseous product ?

asked Nov 8, 2013 by meena.p

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Identify A and B in the following reactions:

asked Nov 8, 2013 by meena.p

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Sodium is heated in air at $300 ^{\circ}C$ to form x.x absorbs $CO_2$ and forms $Na_2CO_3$ and Y. Which of the following is Y?

asked Nov 8, 2013 by meena.p

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Observe the following statements regarding purification of bauxite:

asked Nov 8, 2013 by meena.p

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The chemicals and the reaction conditions required for the preparation of ethane are :

asked Nov 8, 2013 by meena.p

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A complex compound of $Co^{3+}$ with molecular formula $CoCl_x.yNH_3$ gives a total of 3 ions when dissolved in water. How many $Cl^{-}$ ions satisfy both primary and secondary valencies in this complex ?

asked Nov 8, 2013 by meena.p

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In Fischer-Ringe 's method of separation of nobles gas mixture from air, ................... is used:

asked Nov 8, 2013 by meena.p

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A solid mixture 5g consists of lead nitrate and sodium nitrate was heated below $600^{\large\circ}C$ until weight of residue was conotaut.If the loss in weight is 28%,find the amount of lead nitrate and sodium nitrate mixture.

asked Nov 6, 2013 by sreemathi.v

1 answer

Gastric juice contains 3.0g of HCl per litre.If a person produces 2.5l of gastric juice per day,how many antacid tablets each containing 400mg of $Al(OH)_3$ are needed to neutralized all the HCl produced in one day ?

asked Nov 6, 2013 by sreemathi.v

1 answer

How many ml of 0.1N HCl are required to react completely with 1g mixture of $Na_2CO_3$ and $NaHCO_3$ containing equimolar amount of two ?

asked Nov 6, 2013 by sreemathi.v

1 answer

0.5g of a mixture of $K_2CO_3$ and $Li_2CO_3$ required 30ml of 0.25N HCl solution for neutralization.What is % composition mixture ?

asked Nov 6, 2013 by sreemathi.v

1 answer

$0.05\;g$ of a commercial sample $KCl_3$ on decomposition liberated just sufficient oxygen for complete oxidation of $20\;ml\; CO$ at $27^{\large\circ}C$ and $750\;mm$ pressure.Calculate % of $KClO_3$ in sample.

asked Nov 6, 2013 by sreemathi.v

1 answer

$8.0575\times 10^{-2}kg$ of Glauber's salt is dissolved in water.Obtain $1clm^3$ of a solution of density $1077.2kgm^{-3}$.Calculate the molarity and the mole fraction of $Na_2SO_4$ in solution .

asked Nov 6, 2013 by sreemathi.v

1 answer

0.22g sample of volatile compound,containing $C,H$ and $Cl$ only on combustion in $O_2$ gave 0.195g $CO_2$ and 0.0804g $H_2O$.If 0.120g of the compound occupied a volume of 37.24ml at $105^{\large\circ}$ and 768mm of pressure,calculate molecular formula of compound.

asked Nov 6, 2013 by sreemathi.v

1 answer

A mixture in which the mole ratio of $H_2$ and $O_2$ is 2 : 1 is used to prepare water by the reaction $2H_2(g)+O_2(g)\rightarrow 2H_2O(g)$.The total pressure in the container is 0.8atm at $20^{\large\circ}C$ before the reaction.Determine the final pressure at $120^{\large\circ}C$ after reaction assuming 80% yield of water.

asked Nov 6, 2013 by sreemathi.v

1 answer

A gas mixture of $3l$ of propane $(C_3H_8)$ and butane $C_4H_{10}$ on complete combustion at $25C^{\large\circ}$ produced $10l$ $CO_2$.Find out the composition of gas mixture.

asked Nov 6, 2013 by sreemathi.v

1 answer

n-Butane is produced by the monobromination of ethane followed by word reaction .Calculate the volume of ethane at NTP to produce 55g n-butane if the bromination takes place with 90% yield and worth reaction with 85% yield.

asked Nov 6, 2013 by sreemathi.v

1 answer

For the reaction ,$N_2O_5(g)\iff 2NO_2(g)+0.5O_2(g)$.Calculate the mole fraction of $N_2O_5(g)$ decomposed at a constant volume and temperature,if the initial pressure at any time is 960mm Hg.Assume ideal gas behaviour.

asked Nov 6, 2013 by sreemathi.v

1 answer

A sample of Mg was burnt in air to give a mixture of MgO and $Mg_3N_2$.The ash was dissolved in 60meq. of HCl and the resulting solution was back titrated with NaOH.12meq of NaOH were required to reach the end point.An excess of NaOH was added and the solution distilled.The ammonia released was then trapped in 10Meq of second acid solution .Back titration of this solution required 6Meq of the base.Calculate the percentage of Mg burnt to the nitride.

asked Nov 6, 2013 by sreemathi.v

1 answer

Which one of the following is true for an exothermic reaction $ A \rightleftharpoons B$ if $E_{r}\: and \: E_b$ are the activation energies of forward and backward reactions respectively?

asked Nov 5, 2013 by thanvigandhi_1

1 answer

The number of unit cells present in 39 grams of potassium if its crystallizes as body centred cube is : ( N = Avogadro number , At.wt of potassium =39)

asked Nov 5, 2013 by thanvigandhi_1

1 answer

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