Recent questions tagged practical-chemistry

X and Y are two volatile liquids with molar weights of $10\; g\; mol^{–1}$ and $40\; g\; mol^{–1}$ respectively. Two cotton plugs, one soaked in X and the other soaked in Y, are simultaneously placed at the ends of a tube of length $L = 24\; cm$, as shown in the figure. The tube is filled with an inert gas at 1 atmosphere pressure and a temperature of $300\; K$. Vapours of X and Y react to form a product which is first observed at a distance d cm from the plug soaked in X. Take X and Y to have equal molecular diameters and assume ideal behaviour for the inert gas and the two vapours.The experimental value of d is found to be smaller than the estimate obtained using Graham’s law. This is due to:

asked Jan 18, 2016 by meena.p

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Identify the correct order of solubility of $Na_2S, CuS$ and $ZnS$ in aqueous solution

asked Feb 1, 2014 by mosymeow_1

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The reagent $NH_4Cl$ and aqueous $NH_3$ will precipitate

asked Feb 1, 2014 by mosymeow_1

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Potassium ferrocyanide is used in the detection of

asked Feb 1, 2014 by mosymeow_1

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

asked Feb 1, 2014 by mosymeow_1

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Which of the following metal sulphides has maximum solubility in water?

asked Feb 1, 2014 by mosymeow_1

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When chlorine water is added to an aqueous solution of potassium halide in the presence of chloroform, a violet colour is obtained. On adding more of chlorine water, the violet colour disappears, and a colourless solution is obtained. This test confirms the presence of the following in aqueous solution.

asked Feb 1, 2014 by mosymeow_1

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Iodine reacts with $Na_2S_2O_3$ (aq) to give products which are

asked Feb 1, 2014 by mosymeow_1

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Lead has been placed in the group I and II because

asked Feb 1, 2014 by mosymeow_1

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Suspended impurities from a colloidal solution of gum in water can be removed by

asked Feb 1, 2014 by mosymeow_1

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Which of the following can be enthalpy of neutralisation of a weak acid and a strong base?

asked Feb 1, 2014 by mosymeow_1

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If enthalpy of neutralisation of $dil\; HCl$ and $NaOH\; (aq)$ is $x$ then enthalpy of neutralisation of dil HI and $Ba(OH)_2\; (aq)$ is

asked Feb 1, 2014 by mosymeow_1

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Which of the following precipitates $K^+$ from its solution?

asked Feb 1, 2014 by mosymeow_1

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Which of the following is insoluble in dil. $HNO_3$ but soluble in aqua regia?

asked Feb 1, 2014 by mosymeow_1

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When $H_2S$ is passed through an ammoniacal salt solution X, a white ppt. is obtained. Then X can be a

asked Feb 1, 2014 by mosymeow_1

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Distinguishing reagent between silver and lead salts

asked Feb 1, 2014 by mosymeow_1

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$H_2S$ in the presence of HCl precipitates group II but not group IV because

asked Feb 1, 2014 by mosymeow_1

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Concentrated nitric acid is added before proceeding to test for group III members. This is to

asked Feb 1, 2014 by mosymeow_1

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Mg is not precipitated in group V because

asked Feb 1, 2014 by mosymeow_1

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The ion that cannot be precipitated by both HCl and $H_2S$ is

asked Feb 1, 2014 by mosymeow_1

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Which of the following solution gives precipitate with $Pb(NO_3)_2$ but not with $Ba(NO_3)_2$ ?

asked Feb 1, 2014 by mosymeow_1

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An aqueous solution of salt gives white precipitate with $AgNO_3$ solution as well as with dil $H_2SO_4$. It may be

asked Feb 1, 2014 by mosymeow_1

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In a mixture having nitrite and nitrate can be destroyed by heating with

asked Feb 1, 2014 by mosymeow_1

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For the test of halides, the soda extract is acidified with

asked Feb 1, 2014 by mosymeow_1

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Formation of purple colour on the addition of sodium nitroprusside to sodium carbonate extract indicates the presence of

asked Feb 1, 2014 by mosymeow_1

2 answers

A salt solution is acidified with dil. $HCl$ and $BaCl_2$ solution is added. A white ppt. is formed. The salt contains

asked Feb 1, 2014 by mosymeow_1

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Which one of the following cation will give a blue coloured ash when a piece of filter paper dipped in a solution containing its salt and $Co(NO_3)_2$ is burned?

asked Feb 1, 2014 by mosymeow_1

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$H_2S$ and $SO_2$ can be distinguished by

asked Feb 1, 2014 by mosymeow_1

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Acidified $K_2Cr_2O_7$ turns green by

asked Feb 1, 2014 by mosymeow_1

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An inorganic salt when heated evolves a coloured gas which bleaches moist litmus paper. The evolved gas is

asked Feb 1, 2014 by mosymeow_1

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Heating of oxalic acid with conc. $H_2SO_4$ gives

asked Feb 1, 2014 by mosymeow_1

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A test tube containing a nitrate and another containing a bromide and $MnO_2$ are treated with conc. $H_2SO_4$. The brown fumes evolved are passed through water. The water will be coloured by

asked Feb 1, 2014 by mosymeow_1

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When a salt is heated with dil $H_2SO_4$ and $KMnO_4$ solution, the pink colour of $KMnO_4$ is discharged, the mixture contains:

asked Feb 1, 2014 by mosymeow_1

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When borax is heated in a platinum loop, the transparent bead formed contains

asked Feb 1, 2014 by mosymeow_1

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The most suitable indicator for the titrations of $Ba(OH)_2$ against HI is

asked Feb 1, 2014 by mosymeow_1

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If $pK_{in}$ of an indicator is 10.5, the pH transition range for which it is most suitable is

asked Feb 1, 2014 by mosymeow_1

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The most suitable indicator for the titration of HCOOH against NaOH is

asked Feb 1, 2014 by mosymeow_1

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Completion of diazotisation can be checked with

asked Feb 1, 2014 by mosymeow_1

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$C_6H_5OH$ and $C_2H_5OH$ can be distinguished by

asked Feb 1, 2014 by mosymeow_1

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Which of the following compound will give blood red colour while doing the Lassigne's test for N?

asked Feb 1, 2014 by mosymeow_1

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Presence of nitrogen in which of the following compound cannot be detected by Lassaigne's test?

asked Jan 30, 2014 by mosymeow_1

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Flame test is not given by

asked Jan 28, 2014 by mosymeow_1

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$[X] + H_2SO_4 \longrightarrow [Y]$ colourless with irritating smell. $[Y] + K_2Cr_2O_7 + H_2SO_4 \longrightarrow$ Green solution. [X] and [Y] are

asked Jan 28, 2014 by mosymeow_1

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The ion that cannot be precipitated by both $HCl$ and $H_2S$

asked Jan 28, 2014 by mosymeow_1

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Potassium cyanide is used for separating

asked Jan 28, 2014 by mosymeow_1

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How do we differentiate between $Fe^{3+}$ and $Cr^{3+}$ in groupIII?

asked Jan 28, 2014 by mosymeow_1

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When a substance 'A' reacts with water, it produces a combustible gas 'B' and a solution of substance 'C' in water. When another substance 'D' reacts with this solution of 'C', it also produces the same gas 'B' on warming but 'D' can produce gas 'B' on reaction with dilute sulphuric acid at room temperature. 'A' imparts a deep golden yelow colour to the smokeless flame of bunsen flame. 'A', 'B' , 'C' & 'D' are respectively

asked Jan 28, 2014 by mosymeow_1

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Three separate samples of a solution of a single salt gave these results. One formed a white ppt. with excess ammonia solution, one formed a white ppt. with dil. NaCl solution and one formed a black ppt. with $H_2S$. The salt could be:

asked Jan 28, 2014 by mosymeow_1

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The only cations present in a slightly acidic solution are $Fe^{3+}, Zn^{2+}$ and $Cu^{2+}$. The reagent that when added in excess to this solution would identify and separate $Fe^{3+}$ in one step is

asked Jan 28, 2014 by mosymeow_1

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When $K_2Cr_2O_7$ crystals are heated with conc. HCl, the gas evolved is

asked Jan 28, 2014 by mosymeow_1

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