Chemistry

Chemical Reactions and Processes

571 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 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 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.

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

$D _2O$ can be obtained by:

  1. repeated distillation

  2. exchange process

  3. neutron emitting radioactive decay in presence of water

  4. exhaustive electrolysis of alkaline water
Reveal answer Fill a bubble to check yourself
A,B,D Correct answer
Explanation

Heavy water is deuterium oxide $(D _2O)$. Ordinary water contains a fraction (1 in 6000 parts) of heavy water. On large scale, it is produced by repeated electrolysis of ordinary water containing alkali. It is also produced by repeated distillation and condensation. It is also obtained by exchange process.

Multiple choice separation of components of mixtures methods of separation elements, compounds and mixtures chemistry

In a mixture of $NH 3$NH3 and $H _2$, _____ Gets liquified under pressure :

  1. $\displaystyle { H } _{ 2 }$
  2. $\displaystyle { NH } _{ 3 }$
  3. $\displaystyle { H } _{ 2 }O$

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

In a mixture of NH$ _3$ and H$ _2$, NH$ _3$ gets liquefied under pressure
Liquefaction of gases is the process by which a gas is converted to a liquid. In a mixture of NH$ _3$ and H$ _2$, NH$ _3$ gets liquefied under high pressure and H$ _2$ is left behind.
Note: NH$ _3$ has a higher value of the van der Waal's constant 'a' than $H _{2}$
Hence, NH$ _3$ is more easily liquefiable than H$ _2$.

Multiple choice chemistry reactivity series and electrochemistry reactivity series and displacement reactions chemical properties of metals chemical properties of metals and non metals

$Li$, $K$, $Ca$, $Na$, $Mg$, $Al$, $Zn$, $Fe$, $Pb$, $Cu$, $Hg$, $Ag$
Which metal will displace hydrogen from acids but not water?

  1. $Li$
  2. $Na$
  3. $Cu$
  4. $Al$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Aluminium doesn't react with water because, a thin oxidise layer is formed on it. But it reacts with acid and displace Hydrogen in it. Because, The acid react with acidic layer and remove it from Aluminium.  

Multiple choice chemistry reactivity series and electrochemistry reactivity series and displacement reactions chemical properties of metals chemical properties of metals and non metals

A metal 'M' has shining appearance and reacts with hot water and also with dilute hydrochloric acid to evolve hydrogen gas. The metal 'M' is:

  1. can be copper because it lies above hydrogen in the reactivity series, i.e., more reactive than hydrogen

  2. can be gold because it lies below hydrogen in the reactivity series, i.e., more reactive than hydrogen

  3. cannot be gold because it lies above hydrogen in the reactivity series, i.e., less reactivity than hydrogen

  4. cannot be copper because it lies below hydrogen in the reactivity series, i.e., less reactive than hydrogen
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Copper is less reactive than hydrogen and does not displace it from dilute acids. Therefore, a metal that reacts with dilute hydrochloric acid to evolve hydrogen gas cannot be copper.

Multiple choice chemistry reactivity series and electrochemistry reactivity series and displacement reactions chemical properties of metals chemical properties of metals and non metals

Metals above hydrogen in activity series :

  1. react with base to liberate hydrogen ions

  2. react with acids to liberate hydrogen gas

  3. react with water at ordinary temperature

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

The activity series is a listing of the metals in decreasing order of their reactivity with hydrogen ion sources such as water and acids. In the reaction with hydrogen ion source the metal is oxidized to a metal ion and the hydrogen is reduced to hydrogen gas. They are also good reducing agents and poor oxidizing agents.