Advertisements
Advertisements
प्रश्न
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).
Advertisements
उत्तर
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
APPEARS IN
संबंधित प्रश्न
Calculate the amount of carbon dioxide that could be produced when 1 mole of carbon is burnt in air.
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?
Solve the following problem:
Find out the molar mass of the following compounds:
Mohr’s salt [FeSO4(NH4)2SO4.6H2O]
(At. mass: Cu = 63.5; S = 32; O = 16; H = 1; Na = 23; C = 12; Fe = 56; N = 14)
Solve the following problem:
Write the following number in ordinary decimal form:
3.49 × 10−11
Solve the following problem:
Write the following number in ordinary decimal form:
43.71 × 10−4
Perform each of the following calculations. Round off your answers to three digits.
(3.26104) (1.54106)
Solve the following problem:
Perform the following calculation. Round off your answer to three digits.
`((9.28xx10^9)(9.9xx10^-7))/((511)(2.98xx10^-6))`
A 1.000 mL sample of acetone, a common solvent used as a paint remover, was placed in a small bottle whose mass was known to be 38.0015 g.
The following values were obtained when the acetone-filled bottle was weighed: 38.7798 g, 38.7795 g and 38.7801 g. How would you characterise the precision and accuracy of these measurements if the actual mass of the acetone was 0.7791 g?
Solve the following problem:
Your laboratory partner was given the task of measuring the length of a box (approx 5 in) as accurately as possible, using a metre stick graduated in milimeters. He supplied you with the following measurements:
12.65 cm, 12.6 cm, 12.65 cm, 12.655 cm, 126.55 mm, 12 cm.
State which of the measurements you would accept, giving the reason.
What will be the molality of the solution containing 18.25 g of \[\ce{HCl}\] gas in 500 g of water?
Which of the following solutions have the same concentration?
(i) \[\ce{20 g of NaOH in 200 mL of solution}\]
(ii) \[\ce{0.5 mol of KCl in 200 mL of solution}\]
(iii) \[\ce{40 g of NaOH in 100 mL of solution}\]
(iv) \[\ce{20 g of KOH in 200 mL of solution}\]
Match the following physical quantities with units
| Physical quantity | Unit |
| (i) Molarity | (a) g mL–1 |
| (ii) Mole fraction | (b) mol |
| (iii) Mole | (c) Pascal |
| (iv) Molality | (d) Unitless |
| (v) Pressure | (e) mol L–1 |
| (vi) Luminous intensity | (f) Candela |
| (vii) Density | (g) mol kg–1 |
| (viii) Mass | (h) Nm–1 |
| (i) kg |
With increase of temperature, which of these changes?
What quantity (in mL) of a 45% acid solution of a monoprotic strong acid must be mixed with a 20% solution of the same acid to produce 800 mL of a 29.875% acid solution?
The molality of solution containing 15.20 g of urea, (molar mass = 60) dissolved in 150 g or water is ______.
The molarity of urea (molar mass 60 g mol−1) solution by dissolving 15 g of urea in 500 cm3 of water is ______.
