# Mole Fraction

## Trending Questions

**Q.**

**QUESTION 2.5**

A solution of glucose in water is labelled as 10% w/w. What should be the molality and mole fraction of each component in the solution? If the density of solution is 1.2 g mL−1, then what shall be the molarity of the solution?

**Q.**The molarity of 900 g of water is:

- Cannot be calculated
- 50 M
- 55.5 M
- 5 M

**Q.**A solution contains 25% water, 25% ethanol and 50% ethanoic acid by mass. Calculate the mole fraction of each component in the same order.

- 0.301, 0.502, 0.196
- 0.502, 0.196, 0.301
- 0.245, 0.452, 0.502
- 0.502, 0.196, 0.452

**Q.**The mole fraction of the solute in 2.5 molal aqueous solution is:

- 0.051
- 0.043
- 0.156
- 0.43

**Q.**What is the relation between molarity and mole fraction?

**Q.**At 300 K, the vapour pressure of a solution containing 1 mole of n−hexane and 3 moles of n−heptane is 550 mm of Hg. At the same temperature, if one more mole of n-heptane is added to this solution, the vapour pressure of the solution increases by 10 mm of Hg. What is the vapour pressure in mm Hg of n-heptane in its pure state ________?

**Q.**

Which of the following species by definition has ZERO standard Molar enthalpy of formation at 298 K?

${\mathrm{Br}}_{2}\left(\mathrm{g}\right)$

${\mathrm{CH}}_{4}\left(\mathrm{g}\right)$

${\mathrm{Cl}}_{2}\left(\mathrm{g}\right)$

${\mathrm{H}}_{2}\mathrm{O}\left(\mathrm{g}\right)$

**Q.**The relationship between molality (m) and mole fraction (χA) of the solvent is:

- m=XA1−XA×1000XA
- m=1−XAXA×1000MA
- m=1−XAXA×1000XB
- m=XA1−XA×1000XB

**Q.**A sugar syrup (containing sugar and water only) of weight 214.2 g contains 34.2 g of sugar (C12H22O11). Find the mole fraction of the sugar in the syrup.

- 0.1×10−2
- 9.9×10−3
- 9.9×10−4
- 0.1×10−3

**Q.**The vapour density of a mixture containing NO2 and N2O4 is 28.75 at 27oC. Calculate the moles of NO2 in 100 g of the mixture.

- 1.30
- 2.30
- 3.30
- 4.30

**Q.**An aqueous solution is prepared by diluting 3.30 mL of acetone (density = 0.789 g/mL) to get the final volume of 75 mL. Find the mole fraction of acetone. (Assume no volume change on mixing).

- 0.11
- 0.1
- 0.001
- 0.01

**Q.**

QUESTION 2.38

Benzene and naphthalene form ideal solution over the entire range of composition. The vapour pressure of pure benzene and naphthalene at 300 K are 50.71 mm Hg and 32.06 mm Hg respectively. Calculate the mole fraction of benzene in vapour phase if 80 g of benzene is mixed with 100 g of naphthalene.

**Q.**

How can I calculate the molality of pure water?

**Q.**In a 50 mL solution of H2O2 an excess of KI and dilute H2SO4 were added. The I2 liberated required 20 mL of 0.1N Na2S2O3 for complete reaction.

Calculate the strength of H2O2 in grams per litre.

- 0.25 g L−1
- 0.34 g L−1
- 0.68 g L−1
- 0.8 g L−1

**Q.**An ideal gas mixture of ethane (C2H6) and ethene (C2H4) occupies 28 litres at 1 atm and 273 K. The mixture reacts completely with 128 g of O2 to produce CO2 and H2O. The mole fraction of C2H6 in the mixture is:

- 0.6
- 0.4
- 0.5
- 0.8

**Q.**The volume strength of 1 N H2O2 solution is:

- 11.2 V
- 22.4 V
- 1 V
- 5.6 V

**Q.**An ideal solution was obtained by mixing methanol and ethanol. If the partial vapour pressure of methanol and ethanole are 2.619 kPa and 4.556 kPa, respectively, the composition of vapour (in terms of mole fraction) will be

- 0.635 MeOH, 0.365 EtOH
- 0.365 MeOH, 0.635 EtOH
- 0.574 MeOH, 0.326 EtOH
- 0.173 MeOH, 0.827 EtOH

**Q.**21 g of HNO3 is added to 250 mL of water. Then choose the correct option:

- Strength of the solution is 21 g L−1
- Molarity=2.33 M
- Normality=Molarity
- Normality=2.66 N

**Q.**The mass percent of NaOH in water is 4.7%. What is the mole fraction of NaOH in the solution?

- 0.022
- 0.221
- 0.177
- 1.77

**Q.**What mass of ethanol C2H5OH needs to be added to 1.0 kg water so that the mole fraction of ethanol becomes 0.20 ?

- 93.5 g
- 8.3 g
- 638.89 g
- 800 g

**Q.**

Define the following modes of expressing the concentration of a solution? Which of these modes are independent of temperature and why?

(a) w/w (mass percentage)

Define the following modes of expressing the concentration of a solution? Which of these modes are independent of temperature and why?

(b) V/V (volume percentage)

Define the following modes of expressing the concentration of a solution? Which of these modes are independent of temperature and why?

(c) 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?

(d) ppm (parts per million)

Define the following modes of expressing the concentration of a solution? Which of these modes are independent of temperature and why?

(e) x (mole fraction)

Define the following modes of expressing the concentration of a solution? Which of these modes are independent of temperature and why?

(f) M (molarity)

Define the following modes of expressing the concentration of a solution? Which of these modes are independent of temperature and why?

(g) m (molality)

**Q.**49. If two substances A and B have Pa:Pb=1:2 and have mole fraction in solution as 1:2 then mole fraction of A in vapours is A)0.33 B)0.25 C)0.52 D)0.2

**Q.**

Define the following terms:

(i) Mole fraction

(ii) Molality

(iii) Molarity

(iv) Mass percentage.

**Q.**How many grams of oxygen (O2) are required to completely react with 0.20 g of hydrogen (H2) to yield water (H2O)? (molar mass H2=2 g/mol, O2=32 g/mol)

**Q.**At STP the density of CCl4 vapour in g/L will be nearest to:

- 6.87
- 3.42
- 10.26
- 4.57

**Q.**

A hydrocarbon $X$ contains $85.7\%$ carbon by mass. If the relative molecular mass of $X$ is $28$ , find the molecular formula of $X$.

**Q.**45. water is added to the solution M such that the mole fraction of water in the solution becomes 0.9 the booling point of this solution is a) 380.4 k b) 376.2 k c) 375.5 k d) 354.7 k

**Q.**What would be the molality of 20% (mass/mass) aqueous solution of KI ?

Molar mass of KI is 166 g mol−1

- 1.51
- 1.35
- 1.08
- 1.48

**Q.**The OH− concentration in a mixture of 5.0mL of 0.0504 MNH4Cl and 2 mL of 0.0210MNH3 solution is x×10−6M. The value of x is .......(Nearest integer) [Given KW=1×10−14andKb=1.8×10−5]

**Q.**When a coordination compound NiCl2.6H2O is mixed with AgNO3, 2 moles of AgCl are precipitated per mole of the compound. Write:

(i) Structural formula of the complex

(ii) IUPAC name of the complex.