Tag: organic compounds with functional group containing oxygen (part-1)

Questions Related to organic compounds with functional group containing oxygen (part-1)

Rectified spirit can be converted into Absolute alcohol by distilling with?

organic compounds with functional group containing oxygen (part-1) uses of alcohols commercially important alcohols - ethanol some commercially important alcohols

  1. $NaCO _{3}$

  2. $Mg(OC _{2}H _{5}) _{2}$

  3. $CaO$

  4. Both 2 & 3 

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Correct Option: C
Explanation:

In the laboratory, Absolute alcohol is prepared by keeping the rectified spirit in contact with calculated amount of quick lime $(CaO)$ for a few hours and then refluxing and distilling it.

Power alcohol is:

organic compounds with functional group containing oxygen (part-1) uses of alcohols commercially important alcohols - ethanol some commercially important alcohols

  1. absolute alcohol : petrol (20:80)

  2. absolute alcohol : petrol (80:20)

  3. rectified spirit : benzene (20:80)

  4. rectified spirit : benzene (80:20)

Show answer
Correct Option: A
Explanation:

Power alcohol is 20 : 80 mixture of absolute alcohol and petrol.
It is used to generate power.
Power alcohol is an additive to motor fuels to act as fuel for internal combustion engine.

Absolute alcohols (100% ethanol) are prepared from rectified spirit (95% ethanol) by mixing a suitable amount of ............... and subjected to fractional distillation (azeotropic distillation).

organic compounds with functional group containing oxygen (part-1) uses of alcohols commercially important alcohols - ethanol some commercially important alcohols

  1. Toluene

  2. o-Xylene

  3. Methanol

  4. Benzene

Show answer
Correct Option: D
Explanation:

Absolute alcohols (100% ethanol) are prepared from rectified spirit (95% ethanol) by mixing a suitable amount of benzene and subjected to fractional distillation (azeotropic distillation).

Absolute alcohol can be prepared from rectified spirit by _____ distillation.

organic compounds with functional group containing oxygen (part-1) uses of alcohols commercially important alcohols - ethanol some commercially important alcohols

  1. vacuum

  2. fractional

  3. azeotropic

  4. none of these

Show answer
Correct Option: C
Explanation:

Absolute alcohol can be prepared from rectified spirit by azeotropic distillation. Absolute alcohol is 100% pure alcohol. Rectified spirit contains 95.87% ethanol and 4.13% water. It is a constant boiling mixture having boiling point 78.13 $^oC$.

Identify the odd one out from the following.

organic compounds with functional group containing oxygen (part-1) uses of alcohols commercially important alcohols - ethanol some commercially important alcohols

  1. Chloroform

  2. Formaldehyde

  3. Methyl chloride

  4. Methylated spirit

Show answer
Correct Option: D
Explanation:

Denatured alcohol, also called methylated spirits or denatured rectified spirit, is ethanol that has additives to make it poisonous. Rest are made from methane.

Which of the following is used to get absolute alcohol from rectified spirit?

organic compounds with functional group containing oxygen (part-1) uses of alcohols commercially important alcohols - ethanol some commercially important alcohols

  1. $CaO$

  2. $Ca$

  3. $Ca{CO} _{3}$

  4. ${P} _{2}{O} _{5}$

Show answer
Correct Option: A
Explanation:

A rectified spirit is a mixture with a composition of ethanol (95%) and water (5%). Using quicklime $(CaO)$ to absorb water content and finally contacting the solution with anhydrous copper sulphate removes the leftover traces of water that leaves absolute alcohol. 

Methylated spirit is ethanol containing methanol to render it unfit for drinking.

organic compounds with functional group containing oxygen (part-1) uses of alcohols commercially important alcohols - ethanol some commercially important alcohols

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

Methylated spirit is $10\%$ methanol and $90\%$ ethanol which is denatured alcohol used as a solvent and as fuel which is not fit for drinking as it is highly toxic in nature.

Alcohols of low molecular weight are:

chemistry hydroxy compounds and ethers physical properties of phenol physical properties of alcohols and phenols organic compounds with functional group containing oxygen (part-1)

  1. soluble in water

  2. soluble in water on heating

  3. insoluble in water

  4. insoluble in all solvents.

Show answer
Correct Option: A
Explanation:

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 ?

chemistry hydroxy compounds and ethers physical properties of phenol physical properties of alcohols and phenols organic compounds with functional group containing oxygen (part-1)

  1. $CH _3CH _2OH > CH _3CH _2CH _2OH > \underset {(Solubility)}{CH _3CH _2CH _2CH _2OH}$

  2. $CH _3CH _2OH > CH _3CH _2CH _2OH > \underset {(Boiling point)}{CH _3CH _2CH _2CH _2OH}$

  3. $CH _3CH _2CH _2OH > CH _3{\underset{CH _3}{\underset{|}{CH}}}-CH _2OH >\underset{Boiling \, point}{CH _3-\underset{CH _3}{\underset{|}{\overset{CH _3}{\overset{|}C}}}-OH}$

  4. $CH _3-{\underset{CH _3}{\underset{|}{\overset{CH _3}{\overset{|}{C}}}}}-OH$<$CH _3{\underset{CH _3}{\underset{|}{CH}}}-CH _2OH$ <$CH _3CH _2CH _CH _2OH$

Show answer
Correct Option: D
Explanation:
Boiling point and solubility of alcohols is determined by the ease and extent of H-bonding among the alcohol molecules. More is the hydrogen bonding higher is the boiling point and solubility in water. Thus, tertiary alcohols being highly hindered will have least hydrogen bonding and thus low boiling point/solubility as compared to less hindered secondary alcohol.
Therefore the order of boiling point is primary alcohol>secondary alcohol>tertiary alcohol as:
$CH _3CH _2CH _2OH>CH _3CH(CH _3)CH _2OH>CH _3C(CH _3) _2OH$
In case of linear versus branched alcohol, linear alcohol has higher melting/boiling points due to better stacking and surface area contact.
But in case of highly branched vs. branched molecules more sphere-like structure of the molecule better is the stacking thus higher will be the melting point. Thus order of melting point will be
$CH _3CH(CH _3)CH _2OH<CH _3C(CH _3) _2OH<CH _3CH _2CH _2CH _2OH$
A and B. Solubility and boiling point of alcohols depends on the chain length. Longer is the chain length, lesser is the solubility/boiling point as the extent of H-bonding decreases. Also, the hydrophobic nature of the hydrocarbon chain reduces the solubility.
thus order of solubility and boiling point will be:
$CH _3CH _2OH>CH _3CH _2CH _2OH>CH _3CH _2CH _2CH _2OH$

Which of the following is not a characteristic of alcohol ?

chemistry hydroxy compounds and ethers physical properties of phenol physical properties of alcohols and phenols organic compounds with functional group containing oxygen (part-1)

  1. They are lighter than water.

  2. Their boiling points rise fairly uniformly with rising molecular weight.

  3. Lower members are insoluble in water and organic solvents but the solubility regularly increases with molecular mass.

  4. Lower members have a pleasant smell and burning taste, higher members are colourless and tasteless.

  5. Higher members have a pleasant smell and burning taste, lower members are colourless and tasteless.

Show answer
Correct Option: C
Explanation:
A. Alcohols are lighter than water because water molecules are closely packed together due to extensive H-bonding, which means that it has more mass in the same volume than either alcohol or oil. In addition, alcohol is made up of carbon and hydrogen atoms while water is made up of oxygen and hydrogen atoms.
B. Their boiling points rise fairly uniformly with rising molecular weight this is because boiling point depends on the intermolecular interactions such as H-bonding which decreases as the chain length decreases.
C. Lower members are soluble in water and organic solvents but the solubility regularly decreases with molecular mass because of ease of H-bonding in smaller alcohol molecules than those having long hydrocarbon chain.
D. Lower members have a pleasant smell and burning taste, higher members are colourless and tasteless.