Mole Fraction

Q.

A sample of drinking water was found to be severely contaminated with chloroform (CHCl₃). Supposed to be carcinogenic in nature. The level of contamination was 15 ppm (by mass).

(i) Express this in percentage by mass.

(ii) Determine the molality of chloroform in the water sample.

Q. What is mole fraction of solvent in aqueous solution of NaOH having molality 3

Q. Calculate the mass of sodium chloride required to prepare its 20% (mass %) solution in hundred grams of water.

1. 12.5 g
2. 25 g
3. 50 g
4. 20 g

Q.

How many grams of neon $\left(\mathrm{Ne}\right)$ will have the same number of atoms as $4\mathrm{g}$ of calcium $\left(\mathrm{Ca}\right)$?

Q. Mole fraction of the solute in a 1.00 molal aqueous solution is

Q. $100mL$ of $0.6M$ acetic acid is shaken with $2g$ activated carbon. The final concentration of the solution after adsorption is $0.5M$. What is the amount of acetic acid adsorbed per gram of carbon.

1. $0.3$
2. $0.6$
3. $1.8$
4. $1.2$

Q.

What is the mole fraction of the solute in a 1.00 m aqueous solution?

1. 0.0354

2. 1.770

3. 0.0177

4. 0.177

Q.

An empty container was filled with equal masses of methane and hydrogen gases. The fraction of total pressure exerted by hydrogen is____.

1. 1/2

2. 8/9

3. 1/9

4. 16/17

Q. The mole fraction of a solute in a solution is 0.1. At 298 K, molarity of this solution is the same as its molality. Density of this solution at 298 K is 2.0 cc. The ratio of the molecular weights of the solute and solvent, $\left(\frac{M{W}_{solute}}{M{W}_{solvent}}\right)$, is ___

Q. Which of the following expressions can be used for calculating the concentration of a solution formed by dissolving sugar in water?
(More than one option is correct)

1. $\frac{\text{Mass of solvent}\times 100}{\text{Volume of solution}}$
2. $\frac{\text{Volume of solvent}\times 100}{\text{Mass of solution}}$
3. $\frac{\text{Mass of solute}\times 100}{\text{Mass of solute + Mass of solvent}}$
4. $\frac{\text{Volume of solute}\times 100}{\text{Volume of solution}}$

Q. The mole fraction of a solute in a solution is 0.1. At 298 K, molarity of this solution is the same as its molality. Density of this solution at 298 K is 2.0 cc. The ratio of the molecular weights of the solute and solvent, $\left(\frac{M{W}_{solute}}{M{W}_{solvent}}\right)$, is ___

Q.

What is mole fraction represented by?

1. m

2. f

3. x

4. m.f

Q. What is the number of moles of sodium hydroxide contained in $160$ g of it? $[Na=23,O=16,H=1]$

Q.

A solution A has 10 gm of solute B dissolved in 2 moles of solvent. What is the mole fraction of the solute?

1. 10

2. 5

3. 0.833

4. can't be determined

Q. 250mLof a solution is prepared by mixing 0.05 moles of Na2CO3 and 0.1g of Na2CO3. find the molarity of the soliution?

Q.

Calculate the mass of $H_{2}O$ and $C_2{H}_{5}OH$ required to make 640 gm mixture having $X_{H_{2}O}$ and $X_{C_2{H}_{5}OH}$ equal to 0.5

1. 460 gm, 180 gm

2. 640 gm, 640 gm

3. 180 gm, 180 gm

4. 180 gm, 460 gm

Q. How many moles of ${CO}_2$ are in 1.53 g ${CO}_2$?

1. $1.807\times {10}^{-24}$
2. $3.476\times {10}^{-2}$
3. $1.717\times {10}^{-2}$
4. $2.414\times {10}^{-1}$
5. $1.204\times {10}^{24}$

Q.

Mole fractions of A and B in a mixture in which $6.023\times {10}^{23}$ molecules of A and $10.4\times {10}^{23}$ molecules of B are present are:

1. 0.37, 0.37

2. 063, 0.37

3. 0.63, 0.63

4. 0.37, 0.63

Q. What is the mole fraction of the solute in a 1.00 m agueous solution?

1. 0.0354
2. 0.0177
3. 1.77
4. 0.177

Q.

Ordinary water contains one part of heavy water per 6000 parts by weight.The number of heavy water molecules present in a drop of water of volume 0.01 ml is (Density of water is 1 g/ml)

1. 5 X 1016

2. 2.5 X 1016

3. 2.5 X 1017

4. 7.5 X 1016

Q. Equal weights of methane and oxygen are mixed in an empty container at ${25}^{o}C.$ The fraction of the total pressure exerted by oxygen is
(IIT-JEE, 1981)

1. $\frac{1}{3}\times \frac{273}{298}$
2. $\frac{2}{3}$
3. $\frac{1}{2}$
4. $\frac{1}{3}$

Q.

A solution A has 10 gm of solute B dissolved in 2 moles of solvent. What is the mole fraction of the solute?

1. 0.833

2. 10

3. 5

4. can't be determined

Q. For a 50% m/m concentration of a solution with 50 g of solvent, determine the amount of solute to be weighed to obtain the same. (Density = 1 g/L)

1. 25g
2. 50g
3. 50L
4. 25L