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 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.

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

Which of the following statement is incorrect?

  1. Metals like $Cu, Ag, Au$ cannot displace $H$ from acids

  2. In reactivity series metals are arranged in order of increasing reactivity
  3. Silver cannot displace $Cu$ form $Cu(NO _3) _2$
  4. Zinc displaces $Cu$ from $CuSO _4$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In activity series metals are arranged in decreasing order of reactivity. The metals present at top of the series are highly reactive while metals present at the bottom are relatively inert in nature.

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

Metals which loses electrons more easily than hydrogen are more reactive than $H _2$ and they can :

  1. not displace $H _2$ from dilute acids

  2. displace hydrogen from dilute acids

  3. not react with water easily

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

Metals present on top of the reactivity series above the hydrogen can displace the metals present below them from their salt solution.

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

Iron can displace ________ from its solution.

  1. $Cu$
  2. $Al$
  3. $Zn$
  4. $Mg$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Iron can displace $Cu$ from its solution

Reactivity series: Highest $\longrightarrow$ Lowest
$K>Na>Ca>Mg>Al>Zn>Fe>Sn>Pb>Cu>Ag>Au$
Highly reactive elements can displace less reactive elements from their solution.

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

Copper can be displaced from aqueous solution of copper sulphate by adding:

  1. $Ag$
  2. $Au$
  3. $Pt$
  4. $Fe$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

$Fe(s)+CuSO _4(aq)\longrightarrow Cu(s)+FeSO _4(aq)$

Metals like $Zn, Pb, Fe$ and $Al$, displace $Cu$ from copper salt solution.
Reactivity series of metals: $K>Na>Ca>Mg>Al>Zn>Fe>Sn>Pb>Cu>Ag>Au$
So, $K$ is most reactive and $Au$ is least reactive. Metals which are more reactive than that element can displace that element from its salt solution.

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

Mark the incorrect statement.

  1. Reactive metals can displace less reactive metals from their compounds in solution

  2. All metals are not equally reactive

  3. Both A and B

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

Reactive metals can displace less reactive metals from their compounds in solution or molten form. All metals are not equally reactive. Their reactivity is different for different metals.

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

Which of the following will replace hydrogen from acids to form salts?
$S, P, Na, Si$

  1. Sulphur

  2. Phosphorus

  3. Sodium

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

Only those metals which are more reactive than hydrogen, displace hydrogen from acids to form salts and evolve hydrogen gas. Out of the given elements, only $Na$ is a metal which is more reactive than hydrogen.

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

Statement 1: Zinc metal will reduce $Cu^{2+}$ in solution.

Statement 2: Zinc is a more active metal than copper.

  1. <p>Both Statement 1 and Statement 2 are correct and Statement 2 is the correct explanation of Statement 1.</p>

  2. <p>Both Statement 1 and Statement 2 are correct but Statement 2 is the correct explanation of Statement 1.</p>

  3. <p>Statement 1 is correct but Statement 2 is not correct.</p>

  4. <p>Statement 1 is not correct but Statement 2 is correct.</p>

  5. Both the Statement 1 and Statement 2 are not correct.

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In the activity series of metal $Zn$ is above the $Cu$ metal. So it can easily reduce $Cu^{2+}$ in the solution.