Chemistry

Chemical Reactions and Equations

674 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 preparation of haloalkanes halogen derivatives carbon tetrachloride ddt

In the given reaction, identify the compound A.
$3C _2H _5OH+PBr _3\rightarrow A+H _3PO _3$.

  1. $C _2H _5Br$
  2. $CH _3C _2H _5Br$
  3. $CH _2CH _2CH _2CH _2-Cl$

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A is $C _2H _5Br$
$3CH _3-CH _2-OH+PBr _3\rightarrow 3C _2H _5-Br+H _3PO _3$

Multiple choice preparation of haloalkanes halogen derivatives carbon tetrachloride ddt

In the following reaction, identify the compound A.
$3CH _3-CH _2-OH+PCl _3\rightarrow 3C _2H _5-Cl+A$ .

  1. $H _3PO _2$
  2. $H _3PO _3$
  3. $H _3PO _4$
  4. $POCl _3$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A is $H _3PO _3$
$3CH _3-CH _2-OH+PCl _3\rightarrow 3C _2H _5-Cl+H _3PO _3$
Hence option A is correct.

Multiple choice preparation of haloalkanes halogen derivatives carbon tetrachloride ddt

Which of the following is the byproduct when $R-OH$ is reacted with $PCl _3$?

  1. $POCl _3$
  2. $H _3PO _3$
  3. $HCl$

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


$H _3PO _3$ is the byproduct when R-Cl is reacted with $PCl _3$

$3R-OH+PCl _3\rightarrow R-Cl+ H _3PO _3$

In the final product, we get a byproduct of $H _3PO _3$

Hence option B is correct.
Multiple choice preparation of haloalkanes halogen derivatives carbon tetrachloride ddt

In the given reaction, the product formed A and B are :
$3CH _3-CH _2-OH+PCl _3\rightarrow A+B$

  1. $3C _2H _5-Cl+H _2O$
  2. $3C _2H _5-Cl+HCl$
  3. $3C _2H _5-Cl+H _3PO _3$
  4. $3C _2H _5-Cl+POCl _3$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The products formed are $3C _2H _5-Cl+H _3PO _3$ when $3CH _3-CH _2-OH$ is reacted with $PCl _3$.


$3CH _3-CH _2-OH+PCl _3\rightarrow 3C _2H _5-Cl+H _3PO _3$
Hence option C is correct.



Multiple choice preparation of haloalkanes halogen derivatives carbon tetrachloride ddt

In the following reaction which of the following are byproducts?
$C _2H _5OH+PCl _5\rightarrow $

  1. $POCl _3, HCl$
  2. $POCl _2, HCl$
  3. $PCl _3, HCl$

  4. None
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

When ethanol reacts with phosphorous pentachloride, we get ethyl chloride as the main product whereas, phosphorous oxychloride and HCl as the byproducts.

Multiple choice preparation of haloalkanes halogen derivatives carbon tetrachloride ddt

In the following reaction, identify the compound A.
$3CH _3-CH _2-OH+A\rightarrow 3C _2H _5-Cl+H _3PO _3$.

  1. $PCl _3$
  2. $PCl _5$
  3. $POCl _3$
  4. $H _2PO _2$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A is $PCl _3$ in the above reaction.
$3CH _3-CH _2-OH+PCl _3\rightarrow 3C _2H _5-Cl+H _3PO _3$
Hence option A is corrcet.

Multiple choice preparation of haloalkanes halogen derivatives carbon tetrachloride ddt

What is the product formed when $CH _3CH _2CH _2CH _2-OH$ is reacted with $PCl _3$ in presence of trimethyl amine?

  1. $CH _3CH _2CH _2CH _2-Cl$
  2. $CH _3CH(CH _3)CH _2CH _2-Cl$
  3. $CH _3CH _2C(CH _3) _2CH _2-Cl$
  4. $CH _3CH _2CH _2CH _2CH _2CH _2-Cl$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

When Alcohol reacts with $PCl _{3}$ in presence of Trimethyl Amine. It is a nucleophile substitution halogenation reaction replaces $OH^{-}$  with $Cl^{-}$  

   $CH _{3}CH _{2}CH _{2}CH _{2} - OH\overset{PCl _{3}}{\rightarrow} CH _{3}CH _{2}CH _{2}CH _{2} - Cl $

Multiple choice preparation of haloalkanes halogen derivatives carbon tetrachloride ddt

$3C _2H _5OH+A\rightarrow C _2H _5Br+H _3PO _3$.Which of the following is A ?

  1. $PBr _3$
  2. $PBr _5$
  3. $POBr _3$

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The reagent used in the above reaction is $PBr _3$
$3CH _3-CH _2-OH+PBr _3\rightarrow 3C _2H _5-Cl+H _3PO _3$
Hence option A is correct.

Multiple choice preparation of haloalkanes halogen derivatives carbon tetrachloride ddt

$CH _3CH _2C(CH _3) _2CH _2-OH+PCl _3\rightarrow A+H _3PO _4$. In the above reaction which of the following is A?

  1. $CH _3CH _2C(CH _3) _2CH _2-Cl$
  2. $CH _3CH _2CH(CH _3)CH _2-Cl$
  3. $CH _3CH _2CH _2CH _2-Cl$
  4. $CH _3CH(CH _3)C(CH _3) _2CH _2-Cl$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$CH _3CH _2C(CH _3) _2CH _2-OH+PCl _3\rightarrow CH _3CH _2C(CH _3) _2CH _2-Cl+H _3PO _4$
So in the above reaction A is $CH _3CH _2C(CH _3) _2CH _2-Cl$
Hence option A is correct.

Multiple choice preparation of haloalkanes halogen derivatives carbon tetrachloride ddt
Consider the following reaction:
$R-OH+PX _5\rightarrow R-X+B+HX$ 
What is B?
  1. $HPOX _3$
  2. $H _3PO _2$
  3. $H _3PO _3$
  4. $POX _3$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

B is $ \displaystyle POX _3$.
For example, when ethyl alcohol is refluxed with $ \displaystyle PCl _5$, ethyl chloride, HCl and phosphorous oxy chloride is obtained.
$ \displaystyle CH _3-CH _2-OH +PCl _5 \to CH _3-CH _2-Cl+POCl _3+HCl$

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

Give the balance equation for the following laboratory preparation :

Ethane from sodium propionate

  1. $CH _3CH _2COONa + NaOH \rightarrow C _2H _6 + Na _2CO _3$
  2. $CH _3CH _2COONa + 2NaOH \rightarrow C _2H _4 + Na _2CO _3$
  3. $CH _3CH _2COONa + NaOH \rightarrow C _2H _4 + Na _2CO _3$
  4. $CH _3CH _2COONa + 2NaOH \rightarrow 2CH _4 + Na _2CO _3$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Reaction:
$CH _3CH _2COONa + NaOH \rightarrow C _2H _6 + Na _2CO _3$

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.

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