Home
Class 12
CHEMISTRY
A solution of glycerol (C(3) H(8) O(3)) ...

A solution of glycerol `(C_(3) H_(8) O_(3))` in water as prepared by dissolving some glycerol in 500 g of water. This solution has a boiling point of 100 . `42^(@)` C. What mass of glycerol was dissolved to make the solution ? `K_(b) ` for `H_(2) O` = 0 . 512 K kg ` mol^(-1)`

Text Solution

Verified by Experts

The correct Answer is:
37.7 g
`Delta T_(b) = T_(b) - T_(b)^(@) = (100 .42 - 100)^(@)C`
`= 0.42^(@) C = 0.42 K`
`K_(b) = 0.512 K kg mol^(-)`
`W_(A) = 500 g = 0 . 5 kg`
`n_(B) = ?`
`Delta T_(b) = K_() xx (n_(B))/(W_(A) (kg))`
`n_(B) = (Delta T_(b) xx W_(A) (kg))/( K_(b)`
`= ((0.42 K) xx (0.5 kg))/( (0.512 K kg mol^(-1))`
`= (42 xx 5)/( 512) ` mol 0.41 mol
Molar mass of glycerol,
`C_(3) H_(8) O_(3) = (36 + 8 + 48) g mol^(-1)`
`=92 g mol^(-1)`
`n_(B) = (W_(B))/(M_(B))`
`W_(B) = n_(B) xx M_(B) = 0.41mol 92 g mol ^(-1) = 37 . 7 g `
Promotional Banner

Topper's Solved these Questions

  • SOLUTIONS

    BETTER CHOICE PUBLICATION|Exercise Numerical Problems (PSEB 2014)|2 Videos

  • SOLUTIONS

    BETTER CHOICE PUBLICATION|Exercise Numerical Problems (PSEB 2015)|1 Videos

  • SOLUTIONS

    BETTER CHOICE PUBLICATION|Exercise Numerical Problems (PSEB 2012)|6 Videos

  • POLYMERS

    BETTER CHOICE PUBLICATION|Exercise QUESTIONS |42 Videos

  • STRUCTURE OF ATOM

    BETTER CHOICE PUBLICATION|Exercise NUMERICAL PROBLEMS |6 Videos

Similar Questions

Explore conceptually related problems

15 g of an unknown molecular substance was dissolved in 450 g of water. The resulting solution freezes at - 0 . 34^(@) C . What is them molar ass of the substance ? ( K_(f) for water = 1. 86 K kg mol^(-1) )

18 g of glucose is dissolved in 1 kg of water. At what temperature will the solution boil ? ( K_b for water is 0.52 K kg "mol"^(-1) )

A solution of sucrose (molar mass= 342gmol^-1 ) is prepared by dissolving 68.4 g of it per litre of solution. What is the osmotic pressure at 300K?

10g of non-volatile solute when dissolved in 100g of benzene raises its boiling point by 1^@ C. What is the molecular mass of the solute. ( k_b for benzene=2.53 K kg mol^-1 )

A solution containing 12.5 g of a non- electrolyte substance in 175 g of water gave boiling point elevation of 0.70 K. Calculate the molar mass of the substance ( K_b for water = 0.52 K kg mol^(-) ).

A 1.00 molal solution of trichloroacetic acid (CCCl_3COOH) is heated to its boiling point. The solution has the boiling point of 100.18^@C . Determine the Van't Hoff factor for trichloroacetic acid (K_b for water = 0.512 K kg mol^-1)

1 . 5 of Ba (NO_(3))_(2) dissolved in 100 g of water shows a depression in freezing point equal to 0 . 28^(@)C . What is the percentage dissociation of the salt ? ( K_(f) for water = 1 . 86 K/m and molar mass of Ba (NO_(3))_(2) = 261.)

A solution of glucose has been prepared at 298K dissolving 7.2 g of glucose in 100 g of water. k_f water is 1.86Km^-1 and vapour pressure of water at 298K is 0.024 atm. The vapour pressure of the solution at 298K will be

When 36.0 g of a solute having the empirical formula CH_(2)O is dissovled in 1.20 kg of water, the solution freezes at -0.93^(@)C . What is the moleculer formula of the solute ? ( K_(f) = 1.86^(@)C kg mol^(-1) )