Types of Reactions MCQ Quiz - Objective Question with Answer for Types of Reactions - Download Free PDF

The correct answer is Hydrogen gas and iron chloride are produced.

Key Points

• Reaction of hydrochloric acid and Iron:
  • When dilute Hydrochloric acid is added to iron filings, iron chloride & hydrogen gas are produced. 
  • In this reaction, iron displaces hydrogen from hydrochloric acid to form iron chloride and hydrogen gas.
  • The reaction can be represented as:
    • Fe + 2HCl⟶FeCl₂ ​ + H₂ ​  

The correct answer is Na₂O.

Key Points

• Neutral oxides are said to be oxides that do not show any properties of acids and bases.
• Neutral oxide is an oxide that does not react in the presence of any acid or base.
• Let us see other examples of the neutral oxides such as
  • CO
  • N₂O
  • NO
  • MnO₂
  • H₂O

Important Points

• Sodium Oxide having a chemical formula of Na₂O, is a metal oxide.
• It is also known as an alkali metal oxide as it comprises two sodium and one Oxygen atoms.

Additional Information

• Acidic Oxide:
  • It is said to be the oxides when reacted with the water molecule will give acids.
• Basic Oxide:
  • It is said to be the oxides when reacted with water molecules will give bases.
• Amphoteric Oxide:
  • It is said to be the oxides that can react as acid as well as bases.

The Correct answer is Negative, Positive

Key Points

• The negative electrode in a conducting solution is referred to as the cathode, and it is the site where metal deposition occurs during electrolysis.
• At the cathode, positive metal ions in the solution are attracted to the negative charge and undergo reduction reactions, forming a solid metal layer.
• The positive electrode, known as the anode, is responsible for the dissolution of the metal. Here, the metal undergoes oxidation reactions, releasing metal ions into the solution.
• This process is governed by the principles of electrochemistry, which involve the movement of ions and the transfer of electrons between electrodes.
• The direction of ion movement depends on the charge of the electrode—positive ions move towards the cathode, and negative ions move towards the anode.
• The process is widely used in electroplating, purification of metals, and manufacturing through electrochemical methods.
• Examples include gold plating, copper refining, and the deposition of metals in electronic circuits.

Additional Information

• Positive, Negative
  • This option reverses the roles of the electrodes, which is incorrect. In electrolysis, the positive electrode (anode) causes dissolution, not deposition.
• Positive, Positive
  • In this case, assigning the same charge to both electrodes is incorrect. Electrochemical processes require one electrode to be positive (anode) and the other negative (cathode).
• Negative, Negative
  • This option incorrectly states that both electrodes are negative. The cathode is negative, but the anode must be positive for electrolysis to occur.

The correct answer is Chemical.

Key Points

• The formation of carbon dioxide when vinegar and baking soda are mixed is a classic example of a chemical reaction.
• This reaction occurs between acetic acid (present in vinegar) and sodium bicarbonate (baking soda).
• The chemical equation for this reaction is: CH₃COOH + NaHCO₃ → CH₃COONa + H₂O + CO₂.
• During this reaction, new substances like sodium acetate, water, and carbon dioxide gas are formed, which indicates that it is a chemical change.
• The production of bubbles or fizzing in this reaction is due to the release of carbon dioxide gas.
• In a chemical change, the original substances lose their individual properties, and the resulting products have different chemical compositions and properties.
• This type of reaction is an example of an acid-base reaction, where an acid reacts with a base to produce a salt, water, and a gas.

Additional Information

• Physical Change
  • A physical change involves changes in the state, shape, or size of a substance without altering its chemical composition.
  • Examples include melting of ice, boiling of water, or cutting paper.
  • In the case of vinegar and baking soda, the reaction does not only involve a physical transformation; new substances are formed, making it a chemical change.
• Both Physical and Chemical Change
  • A process may involve both physical and chemical changes, but in this case, the dominant change is chemical.
  • For example, the burning of a candle involves a physical change (melting of wax) and a chemical change (burning of wax to produce carbon dioxide and water). However, the reaction between vinegar and baking soda does not have a significant physical change.

The correct answer is Physical, Chemical.

Key Points

• When a candle burns, two processes are happening simultaneously: the melting of wax and the burning of the wick.
• Melting of wax is a physical change because it involves a change in the state of matter (solid to liquid) without altering the chemical composition of the wax.
• The wax does not undergo any transformation in its chemical structure when it melts; it just changes from a solid to a liquid and can be solidified back.
• Burning of the wick is a chemical change because it involves combustion, which is an irreversible process where new substances are formed.
• In the burning process, the wick reacts with oxygen to produce new substances such as carbon dioxide, water vapor, and soot, which signifies a chemical reaction.
• The heat generated from the burning wick also vaporizes the wax, which then burns in the presence of oxygen, further contributing to the chemical change.
• Thus, the overall process involves both physical and chemical changes occurring in tandem.

Additional Information

• Chemical, Physical
  • In this option, the order is reversed. While the burning of the wick is a chemical change, the melting of wax is purely physical. This makes the option incorrect.
• Chemical, Chemical
  • This option assumes both processes are chemical changes, but the melting of wax is a physical process as it doesn’t involve the formation of any new substances.
• Physical, Physical
  • This option assumes both processes are physical changes, but the burning of the wick is a chemical process because it involves combustion and the formation of new substances.

The correct answer is green.

Key Points 

• Barium Nitrate Ba(NO₃)₂ is an Oxidizer used to produce green colour in fireworks and fountains.
• This compound is also used in the production process of Barium Oxide in the vacuum tube industry.
• Barium is also used in medicine and oil and gas production.
• It is an inorganic compound that occurs with other elements like sulfur, oxygen, etc.
• Barium is found at 0.0425% on the earth’s crust, and 13 μg/L in seawater.
• It is a non-combustible compound but enhances the burning of combustible elements.
• The melting point of barium nitrate is 592 degrees Celcius.​

Additional Information

The correct answer is CaSO4.1/2 H2O.

​EXPLANATION:

• Plaster of Paris (POP) is a quick-setting gypsum plaster consisting of a fine white powder (calcium sulfate hemihydrate), which hardens when moistened and allowed to dry.
• It is also known as the Plaster of Paris because for the preparation of POP, the abundant gypsum was first found near the capital city of France i.e. Paris.
• The chemical formula of the Plaster of Paris is CaSO4.\(\frac{1}{2}\) H2O. Therefore option 3 is correct.
• Application of Plaster of Paris is as follows
  1. It is used as a building material as a protective coating on walls and ceilings.
  2. It is used as a moulding and vesting agent for decorative elements.
  3. It is also used for aesthetic touch to the construction elements.
  4. It is also used as plaster in orthopaedics and as a filling material by dentists, etc.

Mistake Points

\(\begin{array}{*{20}{c}} {CaS{O_{4.}} + \frac{1}{2}{H_2}O + 1\frac{1}{2}{H_2}O}\\ {\left( {Plaster\,Of\,Paris} \right)} \end{array} \to \begin{array}{*{20}{c}} {CaS{O_4}.2{H_2}O}\\ {\left( {Gypsum} \right)} \end{array}\)

• Gypsum is an ore of Calcium (Ca). The chemical formula of Gypsum is CaSO4. 2H2O.
• Gypsum is mainly used as a fertilizer, as the main constituent in plaster, chalk, etc.
• The plaster of Paris on mixing with water produces gypsum.
• Calcium Sulphate Hemihydrate (CaSO4·1/2 H2O) on hydration leads to the crystallization of gypsum calcium sulphate dihydrate (CaSO4·2H2O).

The correct answer is Mg(s) + Cl2(g) → Mgcl2(s).

Key Points

• Magnesium (Mg) combines with chlorine (Cl2) to form a new product as magnesium chloride (Mgcl2). Therefore its a combination reaction and the balanced equation can be written as:
  • Mg(s) + Cl2(g) → Mgcl2(s)​

Additional Information

• A combination reaction is a reaction where two or more elements or compounds combine to form a single compound. Such reactions are represented by equations of the following form: X + Y → XY.
• The combination of two or more elements to form one compound is called a combination reaction.
• Other types of Chemical Reactions:
  • Decomposition reaction: The opposite of a combination reaction, a complex molecule breaks down to make simpler ones. Such reactions are represented by equations of the following form: AB → A + B.
  • Precipitation reaction: Two solutions of soluble salts are mixed resulting in an insoluble solid (precipitate) forming. Such reactions are represented by equations of the following form: A + Soluble salt B  → Precipitate + soluble salt C.
  • Neutralization reaction: An acid and a base react with each other. Generally, the product of this reaction is a salt and water. Such reactions are represented by equations of the following form: Acid + Base → Salt + Water.
  • Combustion reaction: Oxygen combines with a compound to form carbon dioxide and water. These reactions are exothermic, meaning they give off heat. Such reactions are represented by equations of the following form: A + O2 → H2O + CO2.
  • Displacement reaction: One element takes place with another element in the compound. Such reactions are represented by equations of the following form: A + BC → AC + B.

The correct answer is an Oxidation reaction.

Key Points

• Rancidity refers to the spoilage of food in such a way that it becomes undesirable for consumption. 
• It is caused by the oxidation of fats and oils present in food.
• It causes changes in the taste and smell of food.

Additional Information

•  Rancidity can be controlled by
  • Adding antioxidants to foods.
  • Keeping food items in a closed container.
  • Refrigerating food.
  • Replacing oxygen in the containers with another gas.

The correct answer is Mg3N2 + 6H2O → 3Mg(OH)2 + 2NH₃

Key Points

• The Displacement reaction is a reaction in which a more reactive element displaces a less reactive element from its compound present in a dissolved state.
• In the Double displacement reaction, there is an exchange of ions between the reactants to give new substances.
• In BaCl2 + H2SO4 → BaSO4 + 2HCl, positive (Ba⁺) and negative(Cl^-) ions of the two reactants switch places forming two new compounds and so it is a double displacement reaction.
  • In this, Barium Chloride (BaCl2) reacts with Sulphuric acid (H2SO4) to form Barium Sulphate (BaSO4) and Hydrochloric acid (HCl).
• In CuSO4 + H2S → CuS + H2SO4, Hydrogen Sulphide (H2S) reacts with Copper (II) Sulphate (CuSO4) and gives Copper Sulphide (CuS) and Sulphuric acid (H2SO4).
  • Here, Cu⁺ and SO₄^- exchange their ions and so, this is a double displacement reaction. 
• In Mg3N2 + 6H2O → 3Mg(OH)2 + 2NH3, Magnesium nitride (Mg3N2) splits into two compounds namely Magnisium Hydroxide (3Mg(OH)2) and Ammonia (2NH3). 
  • A chemical reaction in which a single reactant or compound splits to form simpler products is called a Decomposition reaction.
  • So, this is not a Double displacement reaction, but a Decomposition reaction. Hence option 2 is correct.

Additional Information

• In NaOH + HCl → NaCl + H2O, Sodium (Na+) and OH- exchange ions and so this is a double displacement reaction.
  • This is also a Neutralization reaction because the acid and base reactants neutralize to become salt and water.
  • Sodium Hydroxide (NaOH) is a base and Hydrochloric acid (HCl) is an acid that combines to form a salt (NaCl) and release water (H2O).
• Magnesium nitride is a greenish-yellow colour that is commonly referred to as Trimagnisium dinitride.
  • ​It exists as a powder form at room temperature and normal pressure.
  • It can dissolve in acid and water as well but is slightly soluble in ethanol.
• Hydrogen Sulphide is a colourless chalcogen hydride poisonous and flammable gas with the foul smell of rotten eggs.
• Sulphuric acid also called the Oil of Vitriol has a strong acidic nature and is corrosive.
  • ​At high concentrations, it acts as an oxidizing agent and dehydrating agent.

The correct answer is Hydrogen.

Key Points

• When dilute sulphuric acid is poured on zinc granules, then zinc being more reactive than hydrogen displaces it from the acid and forms zinc sulphate and hydrogen gas. 
  • Zn + H₂SO₄ → ZnSO₄ + H₂.
• Hydrogen is a combustible gas and burns with a popping sound.
• This can be observed when a match stick that is burnt is bought ear to the test tube.

Additional Information

• Hydrogen is the chemical element with the symbol H and atomic number 1. 
• Hydrogen is the lightest element in the periodic table.
• Hydrogen is the most abundant chemical substance in the universe, constituting roughly 75% of all baryonic mass.

The correct answer is Carbon dioxide is liberated.

Key Points

• The reaction between acetic acid and sodium hydrogen carbonate/sodium bicarbonate is shown below:
  • CH3COOH(aq)+NaHCO3(aq)→CH3COONa(aq)+H2O(l)+CO2(g)↑
  • When acetic acid is added to an aqueous solution of sodium bicarbonate, an acid-base reaction takes place (neutralisation reaction)
• Which leads to the formation of a salt of sodium acetate and water along with the evolution of carbon dioxide. 
  • When carbon dioxide is evolved, it appears as a brisk effervescence. Carbon dioxide gas is colourless and odourless.
  • It can be identified by passing it through lime water. If on passing a gas through lime water it turns milky, the gas is carbon dioxide gas. 

The correct answer is Option(2).i.e.Precipitation reaction.

Concept:

Chemical Reactions:

• A process in which one or more compounds are formed as products completely different from the reacting substances is known as a chemical reaction.
• There is generally a change in heat, color, or appearance when a chemical reaction takes place.
• The evolution of gas may also occur.
• A chemical reaction may be reversible or irreversible in nature.
• Chemical changes occur in chemical reactions.

Types of Chemical Reactions-

Different types of reactions are

• Combustion reaction
• Decomposition reaction
• Neutralization reaction
• Precipitation or Double-Displacement Reaction

Explanation:

• Precipitation reactions refer to the formation of insoluble salt when two solutions containing soluble salts are mixed. The insoluble salt that comes out of the solution is known as a precipitate, hence the name of the reaction.
• Precipitation reactions can help to determine the identity of different ions in the solution.

• NaCl + AgNO3 ​→ AgCl + NaNO3​

Mol :     1 mol     1 mol        1 mol      1 mol

Mass:   58.5 g     170 g      143.5 g    85 g

• In the reaction above, AgCl is formed as a precipitate.
• Hence. the reaction Sodium chloride + silver nitrate → silver chloride + sodium nitrate is a precipitation reaction.

Additional Information

Types of Chemical Reactions-The The basis for different types of reactions is the product formed, the changes that occur, the reactants involved, and so on. Different types of reactions are

• Combustion reaction
• Decomposition reaction
• Neutralization reaction
• Precipitation or Double-Displacement Reaction

Combustion Reaction-

• It is a reaction with a combustible material with an oxidizer to give an oxidized product.
• An oxidizer is a chemical a fuel requires to burn, generally oxygen.
• For an example of the combustion of magnesium metal.2Mg + O2→2MgO + Heat Here, 2 magnesium atoms react with a molecule of oxygen-producing 2 molecules of the compound magnesium oxide-releasing some heat in the process.

Decomposition Reaction-

• It is a reaction in which a single component breaks down into multiple products.
• Certain changes in energy in the environment have to be made like heat, light, or electricity breaking bonds of the compound. for example of the decomposition of calcium carbonate giving out CaO (Quick Lime) which is a major component of cement. CaCO3(s)→CaO(s)+CO2(g) Here, the compound Calcium carbonate when heated breaks down into Calcium Oxide and Carbon Dioxide.

Neutralization Reaction-

• It is basically the reaction between an acid and a base giving salt and water as the products.
• The water molecule formed is by the combination of OH- ions and H+ ions. The overall pH of the products when a strong acid and a strong base undergo a neutralization reaction will be 7.
• Consider the example of the neutralization reaction between Hydrochloric acid and Sodium Hydroxide giving out sodium chloride(Common Salt) and water. HCl + NaOH → NaCl + H2O Here, an acid and a base, Hydrochloric acid and Sodium Hydroxide react in a neutralization reaction to produce Sodium Chloride(Common Salt) and Water as the by-products.

The correct answer is

• Nucleophilic addition reaction:
  • These are an important class of reactions that allow the interconversion of C=O (Carbonyl group) into a range of important functional groups.
  • A nucleophile forms a sigma bond with an electron-deficient species under this reaction.

Key Points

• A nucleophilic addition reaction includes three steps:-
  • formation of the new sigma bond between the nucleophile, Nu, to the electrophilic C of the C=O group
  • breaking of the p bond to the O resulting in the formation of an intermediate alkoxide
  • protonation of the intermediate alkoxide to give an alcohol derivative
• The reactivity of carbonyl compounds towards nucleophilic addition reactions depends on the presence of the substituted group.
• Please note that Electron Withdrawing Group (-I, -M) increases reactivity towards nucleophilic addition reaction.
• In option 3, NO₂ shows -M effect. Hence, option 3 is the most reactive for nucleophilic addition reaction.

The correct answer is  Exothermic Reaction.
EXPLANATION:

• An exothermic reaction is a chemical reaction that releases energy in the form of light or heat. The burning of the candle is an exothermic reaction.
• Endothermic reactions - Heat is absorbed, like the Photosynthesis process.
• When Candle burns both physical and chemical changes take place
• Chemical reactions can be classified into five basic types:
  • Combination Reactions - a reaction in which two or more substances combine to form a single new substance.
  • Decomposition Reactions -  a reaction in which a compound breaks down into two or more two simpler substances.
  • Single-Replacement Reactions - a reaction in which one element replaces a similar element in a compound
  • Double-Replacement Reactions - a reaction in which the positive and negative ions of two ionic compounds exchange places to form two new compounds.