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 allotropes of carbon chemistry occurrence of carbon compounds in nature polymers

When super heated steam is passed through white hot wood charcoal, it gets reduced to a mixture of $X, Y$ and this reaction is named as $Z$. Identify $Y$.

  1. $C{O} _{2}$
  2. $S{O} _{2}$
  3. ${H} _{2}$
  4. $N{O} _{2}$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
$X + Y \longrightarrow CO + H _2(water-gas)$
$X = CO$
$Y = H _2$
$XY = water- gas (CO + H _2)$ reaction is exothermic.

$Z$ is known as $carbonisation$ reaction.
Hence, the correct option is C.

Multiple choice

Metal + Acid ->

  1. Salt + Hydrogen

  2. Salt + Water

  3. Salt + Water + Carbon dioxide

  4. Salt + Oxygen
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The general reaction between a metal and an acid is: Metal + Acid yields Salt + Hydrogen gas. This is a classic displacement reaction.

Multiple choice

Which chemicals are produced at the negative electrode?

  1. sodium hydroxide & oxygen gas

  2. hydrochloric acid & chlorine gas

  3. sodium hydroxide & hydrogen gas

  4. sodium hydroxide & oxygen gas
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

During the electrolysis of brine (sodium chloride solution), the negative electrode (cathode) attracts positive sodium ions and produces hydrogen gas through the reduction of water, while sodium hydroxide remains in the solution. Chlorine gas is produced at the positive electrode (anode).

Multiple choice reactions of acids and bases properties of acids and bases acids, bases and salts acids and bases chemistry

When a metal carbonate is treated with dilute hydrochloric acid, the gas liberated is:

  1. hydrogen

  2. chlorine

  3. carbon monoxide

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

When metal carbonate is treated with dilute hydrochloric acid, the products formed are salt, water and carbon dioxide.

This is a type of neutralization reaction but here an intermediate called as carbonic acid is formed $H _2CO _3$, but it gets split into salt, water and carbon dioxide $(CO _2)$, as the intermediate is unstable.
$CO _2$ gas that is produced causes effervescence or bubbling.
Thus, the correct answer is option (D).

Multiple choice reactions of acids and bases properties of acids and bases acids, bases and salts acids and bases chemistry

The metal carbonate will form bubbles giving off carbon dioxide gas and the other products namely :

  1. salt and water

  2. water and heat

  3. water and gas

  4. salt and gas
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

When a metal carbonate reacts with an acid, it produces a salt, water, and carbon dioxide gas. The general equation is: Metal Carbonate + Acid -> Salt + Water + Carbon Dioxide.

Multiple choice reactions of acids and bases properties of acids and bases acids, bases and salts acids and bases chemistry

When are marble chips treated with $HCl$, which of the following gas is liberated?

  1. ${ CO } _{ 2 }$
  2. ${ O } _{ 2 }$

  3. CO
  4. ${ NO } _{ 2 }$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Marble chips are made up of by calcium carbonate. When they are treated with $HCl$, carbon dioxide gas is formed along with water and calcium chloride. ${ CaCO } _{ 3 }+HCl\rightarrow { CaCl } _{ 2 }+{ H } _{ 2 }O+{ CO } _{ 2 }$

Multiple choice reactions of haloarenes haloalkanes and haloarenes chemistry

The interaction of elemental sulphur with Grignard reagent gives ......... .

  1. $H _2S$ gas

  2. Mercaptan

  3. thioalcohol
  4. $R-S-OH$
Reveal answer Fill a bubble to check yourself
B,C Correct answer
Explanation

The interaction of elemental sulphur $(S)$ with grignard reagent $(RMgX)$ gives mercaptan $(RSH)$ which is also called thioalcohol.

Multiple choice reactions of haloarenes haloalkanes and haloarenes chemistry

On reacting with which of the following chemicals sulphur undergoes combination reaction?

  1. metals

  2. nonmetals

  3. acids

  4. alkalies
Reveal answer Fill a bubble to check yourself
A,B Correct answer
Explanation

 On reacting with metals and non metals sulphur undergoes combination reaction.
$\displaystyle Fe+S \rightarrow FeS$
$\displaystyle Cl _2+2S \rightarrow S _2Cl _2$
Note:
A combination reaction (also known as a synthesis reaction) is a reaction where two or more elements or compounds (reactants) combine to form a single compound (product).

Multiple choice redox and stoichiometry applications of redox reaction oxidation- reduction reactions redox reactions chemistry

Give the products available on the cathode and the anode respectively during the electrolysis of an aqueous solution of $MgSO _4$ between inert electrodes.

  1. $O _2$ and $H _2$
  2. $H _2$ and $O _2$
  3. $O _2$ and $Mg$

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

The electrolysis of an aqueous solution of magnesium using inert electrodes produces hydrogen at the cathode and oxygen at the anode and neutral solution of magnesium sulphate remains unaltered by the electrolysis.

Multiple choice action of alkalis on some metals and metal oxides analytical chemistry properties of acids and bases acids, bases and salts chemistry

Which of the following equation is the correct one?

  1. Amphoteric oxide / Hydroxide + acid$\rightarrow$ Salt + Hydrogen
  2. Amphoteric oxide / Hydroxide + alkali$\rightarrow$ Salt + Hydrogen
  3. Metal + alkali$\rightarrow$ Salt + Water
  4. Metal + alkali$\rightarrow$ Salt + Hydrogen
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Amphoteric oxide reacts with acid/alkali to produce salt and water not salt and hydrogen. Also, Metal and alkali react to give salt and liberate hydrogen not water. So, option D is correct.