A solution of glucose in water is labell | Class 12 Chemistry Chapter Solutions, Solutions NCERT Solutions

Question:

A solution of glucose in water is labelled as 10% w/w, what would 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?

Answer:

10% w/w solution of glucose in water means that 10 g of glucose in present in 100 g of the solution i.e., 10 g of glucose is present in (100 - 10) g = 90 g of water.

Molar mass of glucose (C6H12O6) = 6 × 12 + 12 × 1 + 6 × 16 = 180 g mol - 1

Then, number of moles of glucose = 10 / 180 mol

= 0.056 mol

∴ Molality of solution = 0.056 mol / 0.09kg  = 0.62 m

Number of moles of water = 90g / 18g mol-1 = 5 mol

Mole fraction of glucose  (xg) = 0.056 / ( 0.056+5) = 0.011

And, mole fraction of water xw = 1 - xg

= 1 - 0.011 = 0.989

If the density of the solution is 1.2 g mL - 1, then the volume of the 100 g solution can be given as:

= 100g / 1.2g mL-1

= 83.33 mL

=83.33 x 10-3 L

∴ Molarity of the solution = 0.056 mol / 83.33 x 10-3 L

= 0.67 M


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Comments

  • Devanshi patkr
  • 2020-07-31 09:18:41

Thx for helping me 😊


  • Sonali
  • 2019-07-07 19:25:07

1000/90 can be written as 0.09


  • Sonali
  • 2019-07-07 19:24:27

1000/90 can be written as 0.09


  • Nazish
  • 2019-06-08 14:08:32

Why 19 was divided by 18.instead of 180


  • Amarjeet
  • 2019-05-24 18:24:18

From where 0.9 is there


  • Viku
  • 2019-05-20 21:46:16

0.9 kha s aaya h


  • Monika
  • 2019-03-30 10:58:22

When we get 0.01


  • Abab
  • 2019-03-17 15:47:16

Hey


  • Aksh
  • 2019-01-06 19:35:58

What if density is not given


  • Surendra singh kohli
  • 2018-04-25 20:52:10

Very interesting question


Comment(s) on this Question

Welcome to the NCERT Solutions for Class 12 Chemistry - Chapter . This page offers a step-by-step solution to the specific question from Excercise 2 , Question 5: A solution of glucose in water is labelled as 10% w/w, what would be the molality and mole fraction ....