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NEET UG CHEMISTRY MCQ: SOLUTIONS
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Hard
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Analyzing
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Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): At the density of a 5 M solution of [atomic masses of are 39 & 35.5 respectively] is The solution is cooled to The molality of the solution will remain unchanged.
Reason (R) : The molality of a solution does not change with temperature as mass remains unaffected with temperature.
In the light of the above statements, choose the correct answer from the options given below.
Assertion (A): At the density of a 5 M solution of [atomic masses of are 39 & 35.5 respectively] is The solution is cooled to The molality of the solution will remain unchanged.
Reason (R) : The molality of a solution does not change with temperature as mass remains unaffected with temperature.
In the light of the above statements, choose the correct answer from the options given below.
View answer and explanation
Correct option: A
Both (A) and (R) are true and (R) is the correct explanation of (A).
Option A is correct. Molality is defined as moles of solute per kilogram of solvent, which is independent of temperature because mass does not change with temperature. Therefore, both the assertion and reason are true, and the reason correctly explains the assertion.
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Reason: Isotonic solutions have equal osmotic pressure at constant temperature. 0.2 molal aqueous solution of a monobasic acid is 60% ionised. If Kb for water is then the boiling point of the solution will be The vapour pressures of pure liquids and are 400 and 600 mmHg, respectively at 298 K. On mixing the two liquids, the sum of their initial volumes is equal to the volume of the final mixture. The mole fraction of liquid is 0.5 in the mixture. The vapour pressure of the final solution, the mole fractions of components and in vapour phase, respectively are What is molecular weight of a substance whose 7.0% by mass solution in water freezes at . for water is A mixture of ethyl alcohol and propyl alcohol has a vapour pressure of 290 mm at 300 K. the vapour pressure of propyl alcohol is 200 mm. If the mole fraction of ethyl alcohol is 0.6, its vapour pressure (in mm) at the same temperature will be