Tag: physical properties of alcohols and phenols
Questions Related to physical properties of alcohols and phenols
Alcohols of low molecular weight are:
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soluble in water
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soluble in water on heating
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insoluble in water
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insoluble in all solvents.
Alcohols of low molecular weight are soluble in water while that of high molecular weight are insoluble in water .because of high hydrogen bonding in low molecular weight Alcinous.
Which of the following statements is not correctly showing the trend of the properties mentioned ?
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$CH _3CH _2OH > CH _3CH _2CH _2OH > \underset {(Solubility)}{CH _3CH _2CH _2CH _2OH}$
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$CH _3CH _2OH > CH _3CH _2CH _2OH > \underset {(Boiling point)}{CH _3CH _2CH _2CH _2OH}$
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$CH _3CH _2CH _2OH > CH _3{\underset{CH _3}{\underset{|}{CH}}}-CH _2OH >\underset{Boiling \, point}{CH _3-\underset{CH _3}{\underset{|}{\overset{CH _3}{\overset{|}C}}}-OH}$
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$CH _3-{\underset{CH _3}{\underset{|}{\overset{CH _3}{\overset{|}{C}}}}}-OH$<$CH _3{\underset{CH _3}{\underset{|}{CH}}}-CH _2OH$ <$CH _3CH _2CH _CH _2OH$
Which of the following is not a characteristic of alcohol ?
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They are lighter than water.
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Their boiling points rise fairly uniformly with rising molecular weight.
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Lower members are insoluble in water and organic solvents but the solubility regularly increases with molecular mass.
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Lower members have a pleasant smell and burning taste, higher members are colourless and tasteless.
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Higher members have a pleasant smell and burning taste, lower members are colourless and tasteless.
Unlike phenol, 2,4-dinitrophenol is soluble in sodium carbonate solution in water because ?
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presence of two - $NO _2$ groups in the ring makes 2 , 4 - dinitrophenol a stronger acid than phenol.
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presence of two - $NO _2$ groups in the ring makes 2 , 4 - dinitrophenol a weaker acid than phenol.
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presence of two $-NO _2$ groups make the hydrogen bonding easier, making 2 , 4-dinitrophenol soluble.
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nitro group reacts with $Na _2CO _3$ while -$OH$ group does not.
Presence of two electron withdrawing $-No _2$ groups in the ring makes 2,4-dinitrophenol a stronger acid than phenol. Hence it react with aqueous $Na _2CO _3$ solution to form sodium salt thus making it soluble in $Na _2CO _3$ .
The compound which gets dissolved in water is :
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$C _{2}H _{6}$
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$C _{2}H _{4}$
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$C _{2}H _{2}$
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$C _{2}H _{5}OH$
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$C _{3}H _{8}$
Option D or Ethanol dissolves in water.
Which of the following cannot be dissolved in alcohol?
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Dyes and drugs
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Soaps and varnishes
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Resins and varnishes
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Rubber and plastics
Rubber and plastic cannot be dissloved in alchol because of nonpolar nature of rubber and plastics
Which of the following has a higher boiling point?
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Butanol
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Butanal
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Both of them have similar boiling point
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Cannot say anything
There is a large difference between boiling points of butanol and butanal, although they have almost the same solubility in water. Butanol contains -OH group and can form hydrogen bonds. Hence, the molecules are associated. A large amount of energy is required to break the association. Hence, butanol has a higher boiling point. Hydrogen bonding is not possible in butanal.
Solubility of alcohols in water is _______ to that of hydrocarbons of comparable molecular masses.
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greater than
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similar
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lesser than
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none of these
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True
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False
Lower alcohols are more soluble in water than higher alcohols. With the increase in the molar mass, solubility decreases. In alcohols, $-OH$ group is polar and forms hydrogen bonds with water. This makes alcohol water soluble. The alkyl chain (hydrocarbon chain) is non-polar and decreases the solubility of alcohol in water.
Alcohols containing only up to ________________ carbon atoms are completely miscible with water.
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10
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3
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8
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14
Alcohol-containing up to $3-$ carbon atoms are completely miscible with water in all proportions. This is due to the hydrogen bonding with water molecule.