Calculate the Molarity of a Solution of Ethanol in Water in Which the Mole Fraction of Ethanol is 0.040 (Assume the Density of Water to Be One).

Calculate the molarity of a solution of ethanol in water in which the mole fraction of ethanol is 0.040 (assume the density of water to be one).

Numerical

Mole fraction of C₂H₅OH `=("Number of moles of ""C"_2"H"_5"OH")/"Number of moles of solution"`

`0.040="n"_("C"_2"H"_5"OH")/("n"_("C"_2"H"_5"OH")+"n"_("H"_2"O"))` .......(1)

Number of moles present in 1 L water:-

`"n"_("H"_2"O") = (1000 " g")/(18 " g"" mol"^-1)`

`"n"_("H"_2"O") = 55.55 " mol"`

Substituting the value of `"n"_("H"_2"O")` in equation (1),

`"n"_("C"_2"H"_5"OH")/("n"_("C"_2"H"_5"OH")+55.55)=0.040`

`"n"_("C"_2"H"_5"OH") = 0.040 "n"_("C"_2"H"_5"OH") + (0.040)(55.55)`

`0.96" n"_("C"_2"H"_5"OH") = 2.222 " mol"`

`"n"_("C"_2"H"_5"OH") = 2.222/0.96" mol"`

`"n"_("C"_2"H"_5"OH") = 2.314" mol"`

∴ Molarity of solution `=(2.314" mol")/(1 "L")`

= 2.314 M

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Chapter 1: Some Basic Concepts of Chemistry - EXERCISES [Page 28]

Chapter 1 Some Basic Concepts of Chemistry
EXERCISES | Q 1.29 | Page 28

Explain the term Saturated solution giving examples.

Calculate the amount of carbon dioxide that could be produced when 1 mole of carbon is burnt in 16 g of dioxygen.

What is the concentration of sugar (C₁₂H₂₂O₁₁) in mol L^–1 if its 20 g are dissolved in enough water to make a final volume up to 2 L?

Dinitrogen and dihydrogen react with each other to produce ammonia according to the following chemical equation:

\[\ce{N2 (g) + 3H2 (g) → 2NH3 (g)}\]

(i) Calculate the mass of ammonia produced if 2.00 × 10³ g dinitrogen reacts with 1.00 × 10³ g of dihydrogen.

(ii) Will any of the two reactants remain unreacted?

(iii) If yes, which one and what would be its mass?

To make a saturated solution, 36 g of sodium chloride is dissolved in 100 g of water at 293 K. Find its concentration at this temperature.

Explain the term molality