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 chemistry chemical reactions effects of oxidation reactions in daily life corrosion of metals electroplating and its application

Balance the reaction of copper sulphide with dilute hydrochloric acid. 

  1. ${ Cu } _{ 2 }S+2HCl\rightarrow { 2CuCl }+{ H } _{ 2 }S$
  2. ${ Cu } _{ 2 }S+HCl\rightarrow { CuCl }+{ H } _{ 2 }S$
  3. ${ Cu } _{ 2 }S+HCl\rightarrow { CuCl } _{ 2 }+{ H } _{ 2 }+{S}$
  4. $2{ Cu } _{ 2 }S+2HCl\rightarrow 2{ CuCl } _{ 2 }+{ S } _{ 2 }+{H} _{2}S$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$Cu _2S+2HCl\longrightarrow 2CuCl+H _2S$

No. of Atom | No. of Atom | | --- | --- | --- | | $Cu$ |  $2$ | $2$ | | $S$ | $1$ | $1$ | | $H$ | $2$ | $2$ | | $Cl$ | $2$ | $2$ |

Multiple choice chemistry chemical reactions effects of oxidation reactions in daily life corrosion of metals electroplating and its application

Correct balanced equation from the following reactions is:

  1. $S + 3HNO _3 \rightarrow H _2SO _4 + NO _2 + 3H _2O$
  2. $S + HNO _3 \rightarrow H _2SO _4 + 2NO _2 + H _2O$
  3. $S + 3HNO _3 \rightarrow H _2SO _4 + 6NO _2 + 2H _2O$
  4. $S + 6HNO _3 \rightarrow H _2SO _4 + 6NO _2 + 2H _2O$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Reaction:
$S + 6HNO _3 \rightarrow H _2SO _4 + 6NO _2 + 2H _2O$

Multiple choice chemistry chemical reactions effects of oxidation reactions in daily life corrosion of metals electroplating and its application

Give a balanced equation for thermal dissociation of a solid [both containing the chloride ion].

  1. $2{ NH } _{ 4 }Cl\left( s \right) \rightleftharpoons { N _2H _6}\left( g \right) +2HCl\left( g \right) $
  2. ${ NH } _{ 4 }Cl\left( s \right) \rightleftharpoons { NH } _{ 3 }\left( g \right) +Cl _2\left( g \right) $
  3. ${ NH } _{ 4 }Cl\left( s \right) \rightleftharpoons { NH } _{ 3 }\left( g \right) +H _2\left( g \right) $
  4. ${ NH } _{ 4 }Cl\left( s \right) \rightleftharpoons { NH } _{ 3 }\left( g \right) +HCl\left( g \right) $
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

On heating ammonium chloride above 340$^0$C it decomposes into mixture of ammonia and hydrochloric gas. It is a reversible reaction.
${ NH } _{ 4 }Cl\left( s \right) \rightleftharpoons { NH } _{ 3 }\left( g \right) +HCl\left( g \right) $

Multiple choice chemistry nitrogen and sulfur sulfur and its oxides acid deposition natural resources- air, water and land

$ CH _3C \equiv CH \quad \xrightarrow [(HgSO _4]{Dil. H _2SO _4} (B) \xrightarrow [ (NaOH) ]{CHCl _3} (C) $compound (C) can be used as :

  1. an anaesthetic

  2. an insecticide

  3. a solvent

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

The reaction of propyne with HgSO4/H2SO4 gives acetone (B). Acetone reacts with CHCl3/NaOH (haloform-like conditions) to form chloretone (C). Chloretone is used as a hypnotic/sedative.

Multiple choice thermodynamic principles of metallurgy general principles and processes of isolation of elements metallurgy chemistry

Of the following reduction processes, correct processes are :

  1. $Fe _{2}O _{3}$ + $C$ $\rightarrow$ $Fe$
  2. $ZnO$ + $C$ $\rightarrow$ $Zn$
  3. $Ca _{3}(PO _{4}) _{2}$ + $C$ $\rightarrow$ $P$
  4. $PbO$ + $C$ $\rightarrow$ $Pb$
Reveal answer Fill a bubble to check yourself
A,B,C,D Correct answer
Explanation

(A) Carbon reduces ferric oxide to iron. $Fe _2O _3+3C \rightarrow 2Fe + 3CO$.
Thus option A is correct.
(B) Carbon reduces zinc oxide to zinc. $ZnO+C \rightarrow {\triangle} {1673  K} Zn + CO \uparrow$.
Thus option B is correct.
(C) In presence of silica, carbon reduces calcium phosphate to free phosphorus.
$2 Ca _3(PO _4) _2 + 9 SiO _2 + 16 C  \rightarrow 6 CaSiO _3 + P _4 + 16 CO$
Thus option C is correct.
(D) Carbon reduces lead oxide to lead. $2PbO+C \rightarrow 2Pb+CO _2$.
Thus option D is correct.

Multiple choice thermodynamic principles of metallurgy general principles and processes of isolation of elements metallurgy chemistry

Of the following reduction processes, correct processes are:

  1. $Fe _2O _3\,+\,C\,\rightarrow\,Fe$
  2. $ZnO\,+\,C\,\rightarrow\,Zn$
  3. $Ca _3(PO _4) _2\,+\,C\,\rightarrow\,P$
  4. $PbO\,+\,C\,\rightarrow\,Pb$
Reveal answer Fill a bubble to check yourself
A,B,C,D Correct answer
Explanation

All the four processes are correct.
$ZnO+C\overset{1100^{0}C}{\rightarrow}Zn+CO$
$Fe _{2}O _{3}+3C\rightarrow 2Fe+3CO$
$Ca _3(PO _4) _2\,+\,C\,\rightarrow\,2P +3CaO + CO _2$
$PbO\,+\,C\,\rightarrow\,Pb +CO$

Multiple choice thermodynamic principles of metallurgy general principles and processes of isolation of elements metallurgy chemistry

Which of the following reaction represents the action of steam on heated iron?

  1. $3Fe+4H _2O\rightarrow Fe _3O _4+4H _2$
  2. $2Fe+3H _2O\rightarrow Fe _2O _3+3H _2$
  3. $Fe+H _2O\rightarrow FeO+H _2$
  4. $2Fe+H _2O+O _2\rightarrow Fe _2O _3+H _2$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
When steam is passed over a red hot iron to form the ferric oxide and hydrogen gas is released.

The action of steam on heated iron is represented as follows:

$3Fe+4H _2O\rightarrow Fe _3O _4+4H _2$

Hence, option A is the correct answer.
Multiple choice thermodynamic principles of metallurgy general principles and processes of isolation of elements metallurgy chemistry

Of the following reduction processes :

I. $Fe _2O _3\, +\, C\, \rightarrow\, Fe$        

II. $ZnO\, +\, C\, \rightarrow\, Zn$

III. $Ca _3(PO _4) _2\, +\, C\, \rightarrow\, P$

IV. $PbO\, +\, C\, \rightarrow\, Pb$

Correct processes are :

  1. II and IV

  2. III and IV

  3. I , II and IV

  4. all of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The ore is reduced to metal by reduction with carbon. This is carried out during smelting. All the given four processes are correct.

Multiple choice chemistry nitrogen and sulfur ammonia and fertilizers preparation of ammonia-laboratory method and haber's process ammonia

In the preparation of $HNO _{3}$, we get NO gas by catalytic oxidation of ammonia. The moles of NO produced by the oxidation of two moles of $NH _{3}$ will be :

  1. 2

  2. 3

  3. 4

  4. 6
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
In the preparation of $HNO _{3}$, we get NO gas by catalytic oxidation of ammonia.In the below equation 4 moles of $NH _3$ produced 4 moles of $NO$.So the moles of $NO$ produced by the oxidation of two moles of $NH _{3}$ will be2 moles.
$4NH _3+5O _2\rightarrow 4NO+6H _2O$.
Hence option A is correct.
Multiple choice chemistry nitrogen and sulfur ammonia and fertilizers preparation of ammonia-laboratory method and haber's process ammonia

The compound that produces ammonia when treated with sodamide is 

  1. $CH _{3}-CH _{2}-CH=CH _{2}$
  2. $CH _{3}-C\equiv C-CH _{3}$
  3. $CH _{2}=CH-CH=CH _{2}$
  4. $CH _{3}-CH _{2}-C\equiv CH$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

When treated with sodamide (NaNH2), terminal alkynes undergo a deprotonation reaction releasing ammonia gas because terminal alkyne protons are relatively acidic. Among the choices, CH3-CH2-C#CH is a terminal alkyne and will react with sodamide to produce ammonia.

Multiple choice chemistry nitrogen and sulfur ammonia and fertilizers preparation of ammonia-laboratory method and haber's process ammonia

$NH _3$ can't be obtained by :

  1. heating of $NH _4NO _3$ or $NH _4NO _2$
  2. heating $NH _3CI$ or $(NH _4) _2CO _3$
  3. heating of $NH _4NO _3$ with $NaOH$
  4. reaction of $AIN$ or $Mg _3N _2$ or $CaCN _2$ with $H _2O$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Reactions are:
$NH _4NO _3\rightarrow N _2O+H _2O$
$NH _4NO _2\rightarrow N _2+H _2O$
$NH _4Cl\rightarrow NH _3+HCl$
$NH _4NO _3 (aq) + NaOH(s)\rightarrow NH _3(g) +H _2O (l)+ NaNO _3(aq)$
$CaCN _2+3H _2O\rightarrow CaCO _3+NH _3$