Tag: chemistry

Questions Related to chemistry

Which of the following is a chemical change

chemistry phenomena around us changes and its classification types of changes classification of changes

  1. Burning of coal

  2. Dissolving sugar in water

  3. Dissolving salt in water

  4. Melting of ice

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Correct Option: A
Explanation:

A chemical change is the process in which chemical composition of the substance is changed,and physical composition may or may not changed burning of coal that is carbon(C) in presence of oxygen gives a different chemical substance $CO _2$. So, it is a chemical change. Hence option A is correct.

Melting of wax is

chemistry phenomena around us changes and its classification types of changes classification of changes

  1. Reversible change

  2. Irreversible change

  3. Both A,B

  4. None of the above

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Correct Option: A
Explanation:

In melting of wax, only the physical state of the wax changes from solid to liquid. Solid wax can be obtained from molten wax. Molten wax can be again converted to solid wax. This is an example of physical and reversible change. Hence, option A is correct.

Which of the following statements is not correct about methanol?

chemistry chemical reactions of organic compounds commercially important alcohols - methanol methanol some commercially important alcohols uses of alcohols

  1. It is used for drinking purposes.

  2. It is highly poisonous compound.

  3. It can be prepared by reduction of formaldehyde with $LiAlH _4$

  4. It is miscible with water in all proportions.

Show answer
Correct Option: A
Explanation:
Methanol can not be used for drinking purposes as it is highly poisonous compound.
It can be prepared by reduction of formaldehyde with $LiAlH _4$ as :
$HCHO+LiAlH _4 \rightarrow CH _3OH$
It can form hydrogen bond with water and that makes it miscible with water in all proportion.

Methanol can be distinguished from ethanol by the following except :

chemistry chemical reactions of organic compounds commercially important alcohols - methanol methanol some commercially important alcohols uses of alcohols

  1. Reaction with iodine and alkali

  2. Reaction with salicylic acid and ${ H } _{ 2 }{ SO } _{ 4 }$

  3. Reaction with Lucas reagent

  4. Boiling point

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Correct Option: A

The organic compound which when mixed with ethyl alcohol, [ethanol], makes a spurious is:

chemistry chemical reactions of organic compounds commercially important alcohols - methanol methanol some commercially important alcohols uses of alcohols

  1. methanol

  2. methanoic acid

  3. methanal

  4. ethanoic acid

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Correct Option: A
Explanation:

Alcohol is used in large qualities to produce alcoholic ilquiors or beverages throughout the world. Excessive drinking of it damages kidney and produces other vices. So, to refrain people from drinking it, government controls its production and supply . This is done by making it unfit for drinking by addituion of poisonous, substances like methanol, action, pyridine, $CuSO _4.$ It is called methylated spirit/denatured alcohol. 

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

chemistry chemical reactions of organic compounds commercially important alcohols - methanol methanol some commercially important alcohols uses of alcohols

  1. $CH _3OH$

  2. $CH _4$

  3. $CH _2I _2$

  4. $PH _3$

Show answer
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?

chemistry chemical reactions of organic compounds commercially important alcohols - methanol methanol some commercially important alcohols uses of alcohols

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

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

  3. 1-Butanol

  4. 2-Methyl -1-propanol

Show answer
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 :-

chemistry chemical reactions of organic compounds commercially important alcohols - methanol methanol some commercially important alcohols uses of alcohols

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

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

  3. $\displaystyle HCOOH$

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

Show answer
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:

chemistry chemical reactions of organic compounds commercially important alcohols - methanol methanol some commercially important alcohols uses of alcohols

  1. $HCHO$

  2. $CH _{3}COOH$

  3. $HCOOH$

  4. $CH _{3}OH$

Show answer
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:

chemistry chemical reactions of organic compounds commercially important alcohols - methanol methanol some commercially important alcohols uses of alcohols

  1. Mehthyl formate

  2. Ethyl formate

  3. Methyl acetate

  4. Ethyl acetate

Show answer
Correct Option: A
Explanation:

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