Advertisements
Advertisements
प्रश्न
Define Molality.
Advertisements
उत्तर
Molality (m) is defined as the number of moles of the solute per kilogram (kg) of the solvent. It is expressed as:
Molality (m) = `"Moles of solute"/"Mass of solvent in Kg"`
Therefore, the unit of molality is mole per kg (mol kg−1).
If nB moles of solute are dissolved in W grams of solvent, then
Molality = `"n"_"B"/"W" xx 1000`
APPEARS IN
संबंधित प्रश्न
Why is molality of a solution independent of temperature?
Calculate the molarity of the following solution:
30 g of \[\ce{Co(NO3)2 * 6H2O}\] in 4.3 L of solution.
Calculate (a) molality (b) molarity and (c) mole fraction of KI if the density of 20% (mass/mass) aqueous KI is 1.202 g mL−1.
Define Mole fraction.
Define Mass percentage.
Concentrated nitric acid used in laboratory work is 68% nitric acid by mass in aqueous solution. What should be the molarity of such a sample of the acid if the density of the solution is 1.504 g mL−1?
A sample of drinking water was found to be severely contaminated with chloroform (CHCl3) supposed to be a carcinogen. The level of contamination was 15 ppm (by mass):
- express this in percent by mass.
- determine the molality of chloroform in the water sample.
Define molality.
Define Normality.
The sum of all mole fraction for a mixture is always equal to ____________.
1 M, 2.5 litre NaOH solution is mixed with another 0.5 M, 3 litre NaOH solution. Then find out the molarity of the resultant solution:
An X molal solution of a compound in benzene has mole fraction of solute equal to 0.2. The value of X is ____________.
4.0 g of NaOH is dissolved in 100 ml solution. The normality of the solution is ____________.
10 g of NaCl is dissolved in 106 g of the solution. Its concentration is ____________.
5 ml of N HCl, 20 ml of N/2 H2SO4 and 30 ml of N/3 HNO3 are mixed together and volume made to one litre. The normality of the resulting solution is:
Mole fraction of the solute in a 1.00 molal aqueous solution is ____________.
What is the normality of a 1 M solution of H3PO4?
The volume of 4 N HCl and 10 N HCl required to make 1 litre of 6 N HCl are ____________.
Molarity of H2SO4 is 18 M. Its density is 1.8 g/ml. Hence molality is:
200 ml of water is added to 500 ml of 0.2 M solution. What is the molarity of this diluted solution?
For preparing 0.1 N solution of a compound from its impure sample of which the percentage purity is known, the weight of the substance required will be:
A solution made by dissolving 40 g NaOH in 1000 g of water is ____________.
Mole fraction of C3H5(OH)3 in a solution of 36 g of water and 46 g of glycerine is ______.
Out of molality (m), molarity (M), formality (F) and mole fraction (x), those which are independent of temperature are:
4 L of 0.02 M aqueous solution of NaCl was diluted by adding one litre of water. The molality of the resultant solution is ______.
What is the mole fraction of solute in 1.00 m aqueous solutions?
Which of the following is a correct statement for C2H5Br?
Given below are two statements labelled as Assertion (A) and Reason (R).
Assertion (A): Molarity of a solution changes with temperature.
Reason (R): Molarity is a colligative property.
Select the most appropriate answer from the options given below:
Match the terms given in Column I with expressions given in Column II.
| Column I | Column II |
| (i) Mass percentage | (a) `"Number of moles of the solute component"/"Volume of solution in litres"` |
| (ii) Volume percentage | (b) `"Number of moles of a component"/"Total number of moles of all the components"` |
| (iii) Mole fraction | (c) `"Volume of the solute component in solution"/"Total volume of solution" xx 100` |
| (iv) Molality | (d) `"Mass of the solute component in solution"/"Total mass of the solution" xx 100` |
| (v) Molarity | (e) `"Number of moles of the solute components"/"Mass of solvent in kilograms"` |
Define the following modes of expressing the concentration of a solution. Which of these modes are independent of temperature and why?
(iii) w/V (mass by volume percentage)
Define the following modes of expressing the concentration of a solution. Which of these modes are independent of temperature and why?
x (mole fraction)
Match List-I with List-II:
| List-I | List-II |
| A. ppm | I. molL-¹ |
| B. Molarity | II. No units |
| C. Molality | III. Independent of temperature |
| D. Mole fraction | IV. Very dilute solutions |
Choose the correct answer from the options given below:
The concentration of water molecules in pure water at 298 K is?
Carbon percentage (by weight) in crude petroleum may be about
What is the ratio of mass of an electron to the mass of a proton?
What is the normality of 0.3 m H3Pcl solution?
3.36 M sulphuric acid solution is 29% H2SO4 calculate the density of the solution.
The molarity of the solution prepared by dissolving 6.3 g of oxalic acid (H2C2O4 · 2 H2O) in 250 mL of water in mol L-1 is x × 10-2. The value of x is ______. (Nearest integer)
[Atomic mass: H : 1.0, C : 12.0, O : 16.0]
The mole fraction of a solute in a 100 molal aqueous solution is ______ × 10-2. (Round off to the Nearest Integer).
[Given :Atomic masses : H : 1.0 u, O : 16.0 u]
The depression in freezing point of water observed for the same amount of acetic acid, trichloroacetic acid and trifluoroacetic acid increases in the order given above. Explain briefly.
