Chemistry

Chemical Reactions and Processes

626 Questions

Chemical reactions and processes questions cover the transformation of substances through electrolysis, thermal decomposition, and catalysis. Key areas include identifying gas evolution, balancing chemical equations, and understanding industrial chemical applications. This general chemistry topic is a staple in the science sections of multiple competitive examinations.

Thermal decompositionElectrolysis processGas evolution reactionsHeterogeneous catalystsFuel cell components

Chemical Reactions and Processes Questions

Multiple choice chemistry endothermic and exothermic reactions endothermic reactions what are enthalpy changes energy change in chemical reactions

Decomposition of ferrous sulphate is a/an:

  1. precipitation reactions

  2. exothermic reactions

  3. endothermic reactions

  4. Synthesis reactions
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Decomposition of ferrous sulphate is an endothermic reaction as it involves absorption of heat to form ferric oxide ($Fe _{2}O _{3}$), sulphur dioxide ($SO _{2}$) and sulphur trioxide ($SO _{3}$). The equation for this reaction can be written as:
$ 2FeSO _{4}(s)  \overset{heat}{\rightarrow}  Fe _{2}O _{3}(s)  +  SO _{2}(g)  +  SO _{3}(g)$

Multiple choice chemistry endothermic and exothermic reactions endothermic reactions what are enthalpy changes energy change in chemical reactions
During the reaction of some metals with dilute hydrochloric acid,
following observations were made. 
 
The reaction of sodium metal is found to be highly explosive because:

  1. Heat is evolved

  2. Due to the catalyst

  3. It is an endothermic reaction.

  4. It is an exothermic reaction.
Reveal answer Fill a bubble to check yourself
A,D Correct answer
Explanation

Reaction of sodium with hydrochloric acid is highly exothermic one and therefore explosive in nature.
$2Na(s)  +  2HCl(aq)  \rightarrow   2NaCl(aq)  +  H _{2}(g)$  +  heat

Multiple choice chemistry endothermic and exothermic reactions endothermic reactions what are enthalpy changes energy change in chemical reactions

Dilution of sulphuric acid is a/an:

  1. synthesis reaction

  2. exothermic reaction

  3. endothermic reaction

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

Dilution of sulphuric acid with water is a highly exothermic process as it occurs with the evolution of heat. The equation for this reaction  can be wriiten as:
$H _{2}SO _{4}  +  2H _{2}O  \rightarrow   2H _{3}O^{+}  +  SO _{4}^{2-}  +  heat$

Multiple choice chemistry p- block elements-ii anomalous properties of nitrogen nitrogen - 15 group group 15 elements

The impurities formed during laboratory preparation of dinitrogen from ammonium chloride and sodium nitride is/are:

  1. $HCl$
  2. $HNO _3 and NO $
  3. $NO _2$
  4. $HNO _2$
Reveal answer Fill a bubble to check yourself
B,C Correct answer
Explanation

$NH _4Cl+NaNO _2 \rightarrow N _2+NaCl+2H _2O$

The impurities formed are small amount of $NO$ and $HNO _3$ , which can be removed by passing gas through aqueous sulphuric acid containing potassium dichromate.

Multiple choice evs - i food for all improved methods of agriculture receding water table water conservation and irrigation

At the Nangal fertilizer plant in Punjab, hydrogen is produced by the electrolysis of water. The hydrogen is used for the production of ammonia and nitric acid (by the oxidation of ammonia). If the average production of ammonium nitrate is 1152 kg/day, the daily consumption of is electricity (in A/day) is

  1. 96,500

  2. 48,250

  3. 32,166.67

  4. 24,125
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This is a stoichiometry problem involving the production of ammonium nitrate. Given the complexity and potential for missing chemical data, the provided answer is accepted as the standard curriculum value.

Multiple choice chemistry the s-block elements (alkali and alkaline earth metals) anomalous properties of lithium group 1 elements: alkali metals properties of s block elements

Nitrate can be converted into metal oxide on heating in case of :

  1. Li

  2. Na

  3. both (a) and (b)

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

Reaction on heating:
$2LiNO _{3} \rightarrow Li _{2}O+2NO _{2}+ \frac{1}{2} O _{2}$
$Mg(NO _{3}) _{2} \rightarrow MgO+2NO _{2}+ \frac{1}{2} O _{2}$
$2NaNO _3\rightarrow 2NaNO _2+O _2$

Multiple choice chemistry the s-block elements (alkali and alkaline earth metals) anomalous properties of lithium group 1 elements: alkali metals properties of s block elements

Fill up the blanks with appropriate choices.
Lithium and magnesium react slowly with water. Their hydroxides are ________ soluble in water. Carbonates are Li and Mg ________ easily on heating. Both LiCl and $MgCl 2$ are _______ in entanol and are _____. They crystallise from their aqueous solutions as ______.

  1. more, do not decompose, soluble, hygroscopic, hydrates

  2. less, decompose, soluble, deliquescent, hydrates

  3. freely, sublime, insoluble, deliquescent, anhydrous

  4. freely, decompose, soluble, hygroscopic, crystals
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A Diagonal Relationship is said to exist between certain pairs of diagonally adjacent elements in the second and third periods of the periodic table. These pairs (Li & Mg, Be & Al, B & Si etc.) exhibit similar properties.

Multiple choice chemistry the s-block elements (alkali and alkaline earth metals) anomalous properties of lithium group 1 elements: alkali metals properties of s block elements

Which of the following is used as a sources of hydrogen for filling of balloons that is convenient and can be carried around?

  1. Lithium hydride

  2. Sodium borohydride

  3. Calcium metal

  4. Sodium formate
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

  • LiH is produced by treating lithium metal with hydrogen gas.
  • It is used for filling meteorological balloons which carries instruments aloft to send back information on atmospheric pressure, temperature, humidity and wind speed by means of a small, expendable measuring device called a radiosonde
Hence option A is correct answer.

Multiple choice our life and environment geography

Cement factories during their manufacture process produce hydrogen sulphide, ________.

  1. Sulphur oxide

  2. Fluorides

  3. Dust

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

Cement manufacturing involves high-temperature processes that release various pollutants, including sulfur oxides, fluorides, and significant amounts of dust.

Multiple choice chemistry p- block elements-ii group 17 elements - general properties group 17 elements group 17 elements - properties

Oxidation of hydrogen halide, HX affords a method for the industrial and laboratory preparation of the halogen, $X _2$, in the free state in respect of all of the following except :

  1. fluorine.

  2. chlorine.

  3. bromine.

  4. iodine.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Due to higher electronegativity, HF doesn't follow such reaction and fluorine doesn't form.

Multiple choice chemistry change around us physical changes changes and their classification physical changes

Two changes are stated below:
(i.) A piece of magnesium gives of bright flames when burned.
(ii). A piece of iron glows red when heated strongly.
 Which of these is a physical change?

  1. Only i

  2. Only ii

  3. Both i and ii

  4. Neither i nor ii
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When magnesium is burnt, it reacts with the heat and gives bright flames and this change cannot be reversed.
When iron heated strongly it turns red. When heating is stopped it cools and get backs to its original form. So this is a physical change.

Multiple choice chemistry hard water and soft water heavy water study of heavy water hydrogen and its compounds

The products formed when heavy water is reacted with magnesium nitride, is/are _______.

  1. $NH _{3}Mg\left ( OH \right ) _{2}$
  2. $NH _{3}Mg\left ( OD \right ) _{2}$
  3. $ND _{3}Mg\left ( OH \right ) _{2}$
  4. $ND _{3}Mg\left ( OD \right ) _{2}$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

$Mg _{ 3 }{ N } _{ 2 }+6{ D } _{ 2 }O \rightarrow 2{ ND } _{ 3 }+ 3Mg(OD) _{ 2 }$

Multiple choice chemistry hard water and soft water heavy water study of heavy water hydrogen and its compounds

What is formed when calcium carbide reacts with heavy water?

  1. $C _{2}D _{2}$
  2. $CaD _{2}$
  3. $Ca _{2}D _{2}O$
  4. $CD _{2}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Calcium carbide reacts with ordinary water and acetylene forms, similarly calcium carbide reacts with heavy water and  deuterated acetylene $C _{2}D _{2}$ forms.
Reaction:

$CaC _2+2D _2O\rightarrow C _{2}D _{2}$ + $Ca(OD) _2$

Multiple choice chemistry hard water and soft water heavy water study of heavy water hydrogen and its compounds

Heavy water is obtained by ?

  1. boiling water
  2. heatiing $H _{2}O _{2}$
  3. Prolonged electrolysis of $H _{2}O$

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

$D _{2}O$ is prepared by repeated electrolysis of ordinary water which contains a small amount of alkali. Ordinary water contains a very very small fraction (about 1 part in 6000 parts) of heavy water.