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Questions Related to chemistry

Ethanol reacts with sodium and forms two products. These are:

chemistry carbon compounds some important carbon compounds ethanol and ethanoic acid introduction to alcohols - ethanol

  1. sodium ethanoate and hydrogen

  2. sodium ethanoate and oxygen

  3. sodium ethoxide and hydrogen

  4. sodium ethoxide and oxygen

Show answer
Correct Option: C
Explanation:

The equation for the reaction between sodium and ethanol can be written as:
$2CH _{3}CH _{2}OH + 2Na \rightarrow 2CH _{3}CH _{2}ONa + H _{2}$
Therefore, the products formed are sodium ethoxide and hydrogen.

Write the type of reaction.
Ethanol is warmed with ethanoic acid to form ethyl acetate in the presence of concentrated $H _{2}SO _{4}.$

chemistry carbon compounds some important carbon compounds ethanol and ethanoic acid introduction to alcohols - ethanol

  1. Esterification reaction

  2. Neutralisation reaction

  3. Decomposition reaction

  4. Double displacement reaction

Show answer
Correct Option: A
Explanation:

Reaction of ethanol with warm ethanoic acid to form ethyl acetate(an ester) and water can be written as:
$ C _{2}H _{5}OH +  CH _{3}COOH  \overset{H^{+}}{\rightarrow}   CH _{3}COOC _{2}H _{5}  +  H _{2}O$
(ethanol)      (ethanoic acid)             (ester)
Above reaction is an esterification reaction as an alcohol and an acid are combined to formed an ester. 

Which of the following represents saponification reaction?

chemistry carbon compounds some important carbon compounds ethanol and ethanoic acid introduction to alcohols - ethanol

  1. $CH _{3}COONa + NaOH \xrightarrow{CaO} CH _{4} + Na _{2}CO _{3}$

  2. $CH _{3}COOH + C _{2}H _{5}OH \xrightarrow{H _{2}SO _{4}} CH _{3} COOC _{2}H _{5} +H _{2}O$

  3. $2CH _{3}COOH + 2Na \rightarrow 2CH _{3} COONa + H _{2}$

  4. $CH _{3}COOC _{2}H _{5} + NaOH \rightarrow CH _{3} COONa + C _{2} H _{5}OH$

Show answer
Correct Option: D
Explanation:

Saponification is the alkaline hydrolysis of esters to form soap and alcohol. Therefore, the correct answer is option D.

$CH _{3}COOC _{2}H _{5} + NaOH \rightarrow CH _{3}COONa + C _{2}H _{5}OH$
    Ester                         Alkali                Soap               Alcohol

Explain the given reactions with the examples.
Oxidation reaction :

chemistry carbon compounds some important carbon compounds ethanol and ethanoic acid introduction to alcohols - ethanol

  1. ${ C } _{ 2 }{ H } _{ 5 }OH\xrightarrow { Alk.KMn{ O } _{ 4 } } { C }{ H } _{ 2 }OH{ COOH }$

  2. ${ C } _{ 2 }{ H } _{ 5 }OH\xrightarrow { Alk.KMn{ O } _{ 4 } } { C }{ H } _{ 3 }{ CH _3 }$

  3. ${ C } _{ 2 }{ H } _{ 5 }OH\xrightarrow { Alk.KMn{ O } _{ 4 } } { C }{ H } _{ 3 }{ CH _2OH }$

  4. ${ C } _{ 2 }{ H } _{ 5 }OH\xrightarrow { Alk.KMn{ O } _{ 4 } } { C }{ H } _{ 3 }{ COOH }$

Show answer
Correct Option: D
Explanation:

Ethanol is oxidised to ethanoic acid in the presence of alkaline
$KMnO _{4}$ on heating
$CH _{3}  CH _{2}  OH \xrightarrow[Heat]{Alk.  KMnO _{4}} CH _{3}COOH$

An organic compound 'A' produces a gas with brisk effervescence when sodium bicarbonate is added to it. The compound 'A' contains same number of carbons as in ethane. The compound 'A' reacts with ethanol to form a sweet smelling compound 'C' in presence of conc. $H _2SO _4$. A and C respectively are :

chemistry carbon compounds some important carbon compounds ethanol and ethanoic acid introduction to alcohols - ethanol

  1. ethanoic acid and ethyl ethanoate

  2. methanoic acid and ethyl methanoate

  3. ethanoic acid and sodium ethanoate

  4. methanoic acid and sodium methanoate

Show answer
Correct Option: A
Explanation:

Ethanoic acid reacts with sodium bicarbonate, to form carbon dioxide which produces effervescence as: 


$CH _{3}COOH + NaHCO _{3} \rightarrow CH _{3}COONa + H _{2}O + CO _{2}$ 

Also, ethanoic acid reacts with ethanol to form the ester - ethyl ethanoate as follows: 


$CH _{3}COOH + C _{2}H _{5}OH \overset{conc.\ H _{2}SO _{4}}{\longrightarrow} CH _{3}COOCH _{2}CH _{3} + H _2O$ 

Thus, A is ethanoic acid and C is ethyl ethanoate.

Which of the following is a property of ethanol?

chemistry carbon compounds some important carbon compounds ethanol and ethanoic acid introduction to alcohols - ethanol

  1. Ionic compound

  2. Noble gas

  3. Polar covalent compound

  4. Nonpolar covalent compound

  5. Metallic substance

Show answer
Correct Option: C
Explanation:

$C _2H _5OH$ has polar covalent $C-O$ bond due to significant electronegativity difference between $C$ and$ O.$ Similarly $O-H$ bond is also polar covalent due to significant electronegativity difference between $O$ and $H$ atoms.
A covalent bond is formed by sharing of electrons. When this electron sharing is to an equal extent, the bond is non polar covalent. Otherwise the bond is polar covalent.

Name the process for ethanol to ethene conversion and reactants used.
chemistry carbon compounds some important carbon compounds ethanol and ethanoic acid introduction to alcohols - ethanol

  1. hydrogenation of ethanol in the presence of concentrated $H _{2}SO _{4}.$

  2. dehydration of ethanol in the presence of concentrated $H _{2}SO _{4}.$

  3. oxidation of ethanol in the presence of concentrated $H _{2}SO _{4}.$

  4. reduction of ethanol in the presence of concentrated $H _{2}SO _{4}.$

Show answer
Correct Option: B
Explanation:

Ethanol can be converted to ethene as:

    $CH _{3}CH _{2}OH \xrightarrow[hot]{conc.H _{2}SO _{4}} CH _{2}= CH _{2} + H _{2}O$

In above reaction, dehydration of ethanol takes place in the presence of concentrated sulphuric acid.
Hence, the correct option is B.

When most fuels burn, the products include carbon dioxide and X. What is X?

chemistry chemical reactions of organic compounds combustion and thermal cracking of hydrocarbons chemical properties of carbon compounds chemical properties of organic compounds

  1. Hydrocarbons

  2. Hydrogen

  3. Water

  4. Hydroxide

  5. Hydrogen peroxide

Show answer
Correct Option: C
Explanation:

When most fuels burn, the products include carbon dioxide and water.
Fuels are hydrocarbons. Combustion of hydrocarbons releases carbon dioxide and water.
$\displaystyle  CH _4 + 2O _2 \rightarrow CO _2 + 2H _2O$

Petrol engine gives off gaseous oxides of :

chemistry chemical reactions of organic compounds combustion and thermal cracking of hydrocarbons chemical properties of carbon compounds chemical properties of organic compounds

  1. sulphur

  2. phosphorus

  3. carbon

  4. nitrogen

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Correct Option: D
Explanation:

Petrol engine gives off gaseous oxides of nitrogen.
During combustion of fuel at high temperature, nitrogen and oxygen of air combine to form $NO$ and $\displaystyle NO _2$ and are released with the exhaust gas.

Burning of coal and diseal releases:

chemistry chemical reactions of organic compounds combustion and thermal cracking of hydrocarbons chemical properties of carbon compounds chemical properties of organic compounds

  1. $NO _2$

  2. $SO _2$

  3. $CO _2$

  4. None of these

Show answer
Correct Option: A,B,C
Explanation:

Burning of coal and diesel release, sulphur dioxide gas, which is extremely corrosive and suffocating in nature.