Chemistry

Chemical Reactions and Equations

684 Questions

Chemical reactions and equations form a foundational chemistry topic where students identify reaction products, balance chemical formulas, and classify reaction types. It covers critical mechanisms like Markovnikov's rule, precipitation, and endothermic or exothermic processes. These questions are highly common in general science sections of state and central government competitive exams.

Endothermic reactionsPrecipitation reactionsDehydrohalogenation of alkyl halidesChemical equation balancingReaction product identification

Chemical Reactions and Equations Questions

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

$ NaOH+{ C }{ H } _{ 3 }COOH\longrightarrow C{ H } _{ 3 }COONa+{ H } _{ 2 }O $

This reaction is called : 

  1. oxidation reaction

  2. hydrogention reaction

  3. neutralisation reaction

  4. addition reaction
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Acid and Base reacts to form Salt and Water. This reaction is called neutralisation reaction. In this, acid is acetic acid and base is sodium hydroxide. Salt ($CH _3COONa$) is formed.

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

Which of the following product(s) is$/$are obtained during the reaction of ethanoic acid with chlorine?

  1. Monochloroacetic acid

  2. Dichloroacetic acid

  3. Trichloroacetic acid

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

When ethanoic acid reacts with chlorine in the presence of acetic anhydride as catalyst it forms chloroacetic acid.

$CH _3COOH  + Cl _2 \rightarrow ClCH _2COOH + HCl$

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

$2C _3H _8 + 7O _2 \rightarrow 2CO _2 + 8H _2O + 2CO + 2C$ 

Name the type of reaction.

  1. Combustion

  2. Incomplete combustion

  3. Condensation

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The reaction $\displaystyle 2C _3H _8 + 7O _2 \rightarrow 2CO _2 + 8H _2O + 2CO + 2C$  is an example of incomplete combustion reaction. Propane, on incomplete combustion in  presence of excess oxygen gives carbon dioxide, water, carbon monoxide and carbon.

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

 $C _3H _8 + 5O _2\rightarrow  3CO _2 + H _2O$

Name the type of reaction.

  1. Substitution

  2. Combustion

  3. Hydrogenation

  4. Displacement
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The reaction $\displaystyle C _3H _8 + 5O _2\rightarrow  3CO _2 + H _2O$ is an example of combustion reaction. Propane on complete combustion in  presence of excess oxygen gives carbon dioxide and water.

Multiple choice chemistry hydrocarbons introduction to alkenes - ethyne acetylene alkynes

A hydrocarbon of molecular formula , ${C _6}{H _{10}}$ reacts with sodamide and the same on ozonolysis followed by hydrogen peroxide gives two molecules of carboxylic acids, one being optically active. Then the hydrocarbon may be

  1. $1$ hexyne
  2. $2- hexyne$
  3. $3$ hexyne
  4. $3$ methyl $1$ pentyne
Reveal answer Fill a bubble to check yourself
A Correct answer
Multiple choice chemistry hydrocarbons introduction to alkenes - ethyne acetylene alkynes

$C _{2}H _{2}$ on reaction with Na followed by reaction with $C _{2}H _{5}I$ gives 'X'. The molecular formula of 'X' is:

  1. $C _{2}H _{6}$
  2. $C _{4}H _{8}$
  3. $C _{4}H _{6}$
  4. $C _{3}H _{6}$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Reaction: $CH \equiv CH \xrightarrow{Na} Na - C \equiv  CH \xrightarrow{C _2H _5I} C _2H _5 - C \equiv  CH + NaI$


Hence, the correct option is $C$

Multiple choice chemistry hydrocarbons introduction to alkenes - ethyne acetylene alkynes

1, 1, 2, 2-Tetra bromoethane $\xrightarrow {Zn}A$ $\xrightarrow{red hot \ tube}B$,


 Then B is:

  1. Acetylene

  2. Ethylene

  3. Ethane

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

$H-\overset{Br}{\overset{|}{\underset{Br}{\underset{|}{C}}}}-\overset{Br}{\overset{|}{\underset{Br}{\underset{|}{C}}}}-H\xrightarrow[\triangle]{2n}H-C\underset{(A)}{\equiv} C-H\xrightarrow{ red hot \ tube} C _6H _6$


Option D is correct.

Multiple choice chemistry hydrocarbons introduction to alkenes - ethyne acetylene alkynes

Which of the following reaction will give acetylene as a major product?

  1. $2[CH _{3}] \underset {\triangle}{\xrightarrow {Ag}}$
  2. $H _{3}C - CH _{2} - Br\underset {KOH}{\xrightarrow {alc.}}$
  3. $\underset {\underset {Br}{|}}{CH _{2}} - \underset {\underset {Br}{|}}{CH _{2}} \underset {\triangle}{\xrightarrow {Zn}}$

  4. All of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Only $2[CH _3] \xrightarrow[\Delta]{Ag} HC \equiv CH$ give acetylene

$B)$ $H _3C - CH _2 - Br \xrightarrow[KOH]{ak} CH _2 = CH _2$
$C)$ $\underset{Br}{\underset{|}{CH _2}} - \underset{Br}{\underset{|}{CH _2}} \rightarrow H _2C = CH _2$

Multiple choice chemistry hydrocarbons introduction to alkenes - ethyne acetylene alkynes

Ethene is obtained by dehydrobromination of:

  1. CHBr = CHBr
  2. $CH _3CHBr _2$
  3. $CH _3 - CH _2Br$

  4. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Dehydrobromination is an organic reaction in which alkyl halide when boiled with alc.alkali gives corresponding alkene called as beta-elimination reaction.

Multiple choice distinction between pairs of amines organic compounds containing nitrogen organic compounds with functional group containing nitrogen chemistry

Nitration of acetanilide followed by hydrolysis gives

  1. Ortho nitro aniline

  2. Para nitroaniline

  3. Ortho and para nitroaniline

  4. Ortho nitro anilinium ion
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Acetanilide is nitrated to form p-nitroacetanilide because the acetamido group is bulky, directing substitution to the para position. Subsequent hydrolysis of the amide group yields para-nitroaniline.

Multiple choice distinction between pairs of amines organic compounds containing nitrogen organic compounds with functional group containing nitrogen chemistry

p-chloroaniline and anilinium hydrochloride can be distinguished by :

  1. $Sandmeyer $ $reaction$
  2. $\displaystyle NaHCO _{3}$
  3. $\displaystyle AgNO _{3}$
  4. $carbylamines$ $ test$
Reveal answer Fill a bubble to check yourself
B,C Correct answer
Explanation

p-chloroaniline and anilinium hydrochloride can be distinguished by by using $AgNO _3$ and $NaHCO _3$, With $AgNO _3 $ anilinium hydrochloride gives white precipitate of $AgCl$. 


$NaHCO _3$ is a weak acid  which solublize anilinium hydrochloride and $CO _2$ gas liberates but  p-chloroaniline do not react with them.