Question 14 Marks
Read the following text carefully and answer the questions that follow:
The boiling point elevation and the freezing point depression of solutions have a number of practical applications. Ethylene glycol $(CH_2OH$-$CH_2OH)$ is used in automobile radiators as an antifreeze because it lowers the freezing point of the coolant. The same substance also helps to prevent the radiator coolant from boiling away by elevating the boiling point. Ethylene glycol has a low vapour pressure. We can also use glycerol as an antifreeze. In order for boiling point elevation to occur, the solute must be non$-$volatile, but no such restriction applies to freezing point depression. For example, methanol $(CH_3OH),$ a fairly volatile liquid that boils only at $65^\circ C$ is sometimes used as antifreeze in automobile radiators.
$i.$ Out of the $CH_3OH$ and $C_6H_{12}O_6,$ which is a better reagent for depression in freezing point but not for elevation in boiling point?
$ii.$ Will the depression in freezing point be same or different, if $0.1 \ moles$ of sugar or $0.1 \ moles$ of glucose is dissolved in $1 L$ of water?
$iii. 124 g$ each of the two reagents glycerol and glycol are added in $5 \ kg$ water of the radiators in the two cars. Which one is better for a car? Justify your answer.
$OR$
$iiii.$ If the cost of glycerol, glycol and methanol are the same, then what would be the sequence of the economy to use these compounds as antifreeze?
The boiling point elevation and the freezing point depression of solutions have a number of practical applications. Ethylene glycol $(CH_2OH$-$CH_2OH)$ is used in automobile radiators as an antifreeze because it lowers the freezing point of the coolant. The same substance also helps to prevent the radiator coolant from boiling away by elevating the boiling point. Ethylene glycol has a low vapour pressure. We can also use glycerol as an antifreeze. In order for boiling point elevation to occur, the solute must be non$-$volatile, but no such restriction applies to freezing point depression. For example, methanol $(CH_3OH),$ a fairly volatile liquid that boils only at $65^\circ C$ is sometimes used as antifreeze in automobile radiators.
$i.$ Out of the $CH_3OH$ and $C_6H_{12}O_6,$ which is a better reagent for depression in freezing point but not for elevation in boiling point?
$ii.$ Will the depression in freezing point be same or different, if $0.1 \ moles$ of sugar or $0.1 \ moles$ of glucose is dissolved in $1 L$ of water?
$iii. 124 g$ each of the two reagents glycerol and glycol are added in $5 \ kg$ water of the radiators in the two cars. Which one is better for a car? Justify your answer.
$OR$
$iiii.$ If the cost of glycerol, glycol and methanol are the same, then what would be the sequence of the economy to use these compounds as antifreeze?
Answer
View full question & answer→$i. CH_3OH$ is a better reagent for depression in freezing point but not for elevation in boiling point.
$ii.$ The depression in freezing point will be the same in both the solutions because both are non$-$electrolytes and gives the same number of solutes.
$iii.$ Glycol will be better than glycerol because it is more volatile than glycerol.
$ii.$ The depression in freezing point will be the same in both the solutions because both are non$-$electrolytes and gives the same number of solutes.
$iii.$ Glycol will be better than glycerol because it is more volatile than glycerol.