EASY
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The mole-fraction of a solute in one molal ethanolic solution would be (Given, molecular mass of ethanol =46.07 g.mol-1 )

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Important Questions on Some Basic Concepts of Chemistry

EASY
What would be the molality of 20% (mass/mass) aqueous solution of KI ? (molar mass of KI=166 g mol-1 )
EASY
Which of the following is dependent on temperature?
MEDIUM
The mole fraction of a solvent in aqueous solution of a solute is 0.8. The molality (in mol kg-1 ) of the aqueous solution is:
EASY
A solution of sodium sulphate contains 92 g of Na+ ions per kilogram of water. The molality of Na+ ions in that solution in mol kg-1 is:
EASY
The weight percent of sucrose (formula weight =342 g mol-1 ) in an aqueous solution is 3.42. The density of the solution is 1 g mL-1, the concentration of sucrose in the solution in mol L-1 is
MEDIUM
The standard enthalpies of formation of H2O(l) and CO2(g) are respectively -286kJ mol-1 and -394kJ mol-1. If the standard heat of combustion of CH4(g) is -891kJ mol-1, then the standard enthalpy of formation of CH4(g) is
MEDIUM
Dissolving 120 g of a compound of (mol. wt. 60) in 1000 g of water gave a solution of density 1.12 g/mL. The molarity of the solution is :
MEDIUM
A gas mixture contains 25% He and 75% CH4 by volume at a given temperature and pressure. The percentage by mass of methane in the mixture is approximately ___ .
HARD
If Avogadro's number is A0 , the number of sulphur atoms present in 200 mL of 1N H2SO4 is
MEDIUM
A solution (5 mL) of an acid X is completely neutralized by y mL of 1M NaOH. The same volume (y mL) of 1M NaOH is required to neutralize 10 mL of 0.6 M H2SO4 completely. The normality (N) of the acid X is
MEDIUM
In which one of the following reactions, entropy decreases?
EASY
What is mole fraction of the solute in a 1.00 m aqueous solution?
EASY
Dissolving 120 g of urea in 1000 g of water gave a solution of density 1.15g/mL. The molarity of the solution is:
MEDIUM
A solution is prepared by dissolving 20g NaOH in 1250mL of a solvent of density 0.8g/mL. Then the molality of the solution is;
EASY
Calculate the concentration of the 2%(w/w)NaCl solution in terms of molality.
EASY
While combusting in air, 4 g of H2 gas was completely converted into water. If 36μmole of CO2 from air is dissolved into that water, what is the concentration of CO2 ?
EASY
A litre of seawater (which weighs 1030 g) contains 6×10-3 g of dissolved oxygen. The concentration of dissolved oxygen in ppm is:
HARD
What quantity (in mL) of a 45% acid solution of a mono-protic strong acid must be mixed with a 20% solution of the same acid to produce 800 mL of a 29.875% acid solution?
MEDIUM
The molality of solution containing 15.20 g of urea, (molar mass = 60) dissolved in 150 g of water is
EASY
8 g of NaOH is dissolved in 18g of H2O. Mole fraction of NaOH in solution and molality (in  mol kg-1) of the solution respectively are: