Tag: some commercially important alcohols

Questions Related to some commercially important alcohols

Methyl alcohol is treated with conc HI and red P. The main product obtained is ?

  1. $CH _3OH$

  2. $CH _4$

  3. $CH _2I _2$

  4. $PH _3$


Correct Option: B
Explanation:
$HI$/Red P is one of the strongest reducing agents. So, it reduces all functional groups to yield alkanes. Hence, methanol gives methane.
$CH _{3}OH \, \overset{HI/Red\, P}\rightarrow \,CH _{4}$

Which of the following is wood alcohol?

  1. $\displaystyle CH _{3}OH$

  2. $\displaystyle C _{2}H _{5}OH$

  3. 1-Butanol

  4. 2-Methyl -1-propanol


Correct Option: A
Explanation:

Methanol, also known as methyl alcohol, wood alcohol, wood naphtha, methyl hydrate, or wood spirits, is a chemical with the formula CH₃OH.


Methanol acquired the name wood alcohol because it was once produced chiefly by the destructive distillation of wood

Hence, the correct option is $\text{A}$

Carbinol is a trivial name of :-

  1. $\displaystyle { C } _{ 2 }{ H } _{ 5 }OH$

  2. $\displaystyle { CH } _{ 3 }OH$

  3. $\displaystyle HCOOH$

  4. $\displaystyle { CH } _{ 3 }COOH$


Correct Option: B
Explanation:

Carbinol is a trivial name of methanol $CH _3OH$.

$(CO+H _{2})+H _{2}\overset {673k,300atm,/Cr _{2}O _{3}-ZnO} {\rightarrow}$ 
The above shown reaction may by used for manufacture of:

  1. $HCHO$

  2. $CH _{3}COOH$

  3. $HCOOH$

  4. $CH _{3}OH$


Correct Option: D
Explanation:

Methanol is prepared on an industrial scale from a mixture of CO and H2. The mixture is subjected to 200atm pressure and passed over ZnO and Cr2O3 catalyst at 400 to 450 degrees celsius.

Hydrolysis of an ester gives acid A and alcohol B. The acid reduces Fehlings solution. Oxidation of alcohol B gives acid A. The ester is:

  1. Mehthyl formate

  2. Ethyl formate

  3. Methyl acetate

  4. Ethyl acetate


Correct Option: A
Explanation:

A
A:- HCOOH
B:- $CH _{3}OH$
Therefore the ester is $HCOOCH _{3}$

Methanol is now prepared from:

  1. water gas

  2. sugar through fermentation

  3. wood

  4. both $A$ and $B$


Correct Option: D
Explanation:
On an industrial scale, methanol is predominantly produced from natural gas by reforming the gas with steam and then converting and distilling the resulting synthesized gas mixture to create pure methanol. The result is a clear, liquid, organic chemical that is water-soluble and readily biodegradable.
Some methanol can be produced during fermentation, but this is not derived from the ethanol or by carbohydrate oxidation. It is produced in small amounts, either by non-enzymatic reactions or through the reduction of formaldehyde.

What is the common name of methyl alcohol?

  1. Wine

  2. Wood spirit

  3. Dilute acid

  4. None of the above


Correct Option: B
Explanation:

 Methanol acquired the name wood spirit because it was once produced chiefly by the destructive distillation of wood.

Which among the following reactions does not give methyl alcohol?

  1. The reaction of ethylene with ${H} _{2}{SO} _{4}$ at ${80}^{o}C$

  2. The reaction of water gas with hydrogen at high temperature

  3. Alkaline hydrolysis of methyl bromide

  4. Both $A$ and $B$


Correct Option: A
Explanation:

The reaction of ethylene with ${H} _{2}{SO} _{4}$ at ${80}^{o}C$ gives ethyl hydrogensulphate.
$CH _2=CH _2+H _2SO _4 \rightarrow CH _3CH _2OSO _2OH$
Water gas (carbon monoxide and hydrogen) at high temperature gives methanol.
$CO + 2H _2 \rightarrow CH _3OH$.
Alkaline hydrolysis of methyl bromide gives methanol 
$CH _3Br + H _2O \rightarrow CH _3OH + HBr$

Methanol can be prepared when :

  1. iodomethane is heated with moist silver oxide

  2. iodomethane react with sodium in the presence of ether

  3. both A and B

  4. none of these


Correct Option: A
Explanation:
Moist Silver oxide 
$Ag _2O + H _2O \rightarrow 2AgOH$
$CH _3-I + AgOH \rightarrow CH _3-OH + AgI$
Therefore, methanol can be prepared when iodomethane is heated with moist silver oxide. 

There are two samples $A$ and $B$. $A$ is Methanol and $B$ is Ethanol. Both are heated both at the same rate in closed container separately. Which one is correct about the above test?

  1. At $60^0$C, container $A$ and $B$ both have liquids in them

  2. At $80^0$C, container $A$ and $B$ both have vapours in them

  3. At $70^0$C, container $B$ has liquid and $A$ has vapours

  4. All the above


Correct Option: D
Explanation:

Methanol has a boiling point of $64.7^0$C whereas ethanol has a boiling point of $78.24^0$C. So, all the statements are correct.