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

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

  1. sodium ethanoate and hydrogen

  2. sodium ethanoate and oxygen

  3. sodium ethoxide and hydrogen

  4. sodium ethoxide and oxygen
Reveal answer Fill a bubble to check yourself
C Correct answer
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.

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

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

  1. Esterification reaction

  2. Neutralisation reaction

  3. Decomposition reaction

  4. Double displacement reaction
Reveal answer Fill a bubble to check yourself
A Correct answer
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. 

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

Which of the following represents saponification reaction?

  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. $CH _{3}COOC _{2}H _{5} + NaOH \rightarrow CH _{3} COONa + C _{2} H _{5}OH$
Reveal answer Fill a bubble to check yourself
D Correct answer
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

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

Explain the given reactions with the examples.
Oxidation reaction :

  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. ${ C } _{ 2 }{ H } _{ 5 }OH\xrightarrow { Alk.KMn{ O } _{ 4 } } { C }{ H } _{ 3 }{ COOH }$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

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

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

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 :

  1. ethanoic acid and ethyl ethanoate

  2. methanoic acid and ethyl methanoate

  3. ethanoic acid and sodium ethanoate

  4. methanoic acid and sodium methanoate
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

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

Which of the following is a property of ethanol?

  1. Ionic compound

  2. Noble gas

  3. Polar covalent compound

  4. Nonpolar covalent compound

  5. Metallic substance
Reveal answer Fill a bubble to check yourself
C Correct answer
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.

Multiple choice chemistry carbon compounds some important carbon compounds ethanol and ethanoic acid introduction to alcohols - ethanol
Name the process for ethanol to ethene conversion and reactants used.
  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 $H _{2}SO _{4}.$
Reveal answer Fill a bubble to check yourself
B Correct answer
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.

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

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

  1. Hydrocarbons

  2. Hydrogen

  3. Water

  4. Hydroxide

  5. Hydrogen peroxide
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

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

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

Petrol engine gives off gaseous oxides of :

  1. sulphur

  2. phosphorus

  3. carbon

  4. nitrogen
Reveal answer Fill a bubble to check yourself
D Correct answer
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.