There are no items in your cart
Add More
Add More
| Item Details | Price | ||
|---|---|---|---|
Welcome to our AJs Chalo Seekhen. This webpage is dedicated to Class 10 Science Chapter 1 -Chemical Reactions and Equations. Here, you will find a comprehensive collection of important questions and answers that cover the key concepts and topics discussed in this chapter. Whether you're a student looking for exam preparation or a teacher seeking additional resources, our webpage provides a valuable resource to enhance your understanding of the fundamental unit of life, including cell structure, functions, and various types of cells. Dive into our carefully curated questions and answers to strengthen your knowledge and excel in your science studies.
In Activity 1.9, the steps involved are as follows:
The purpose of cleaning the iron nails with sandpaper is to remove any impurities or oxide layers present on the surface of the nails. This ensures a clean surface for the iron nails to interact with the copper sulphate solution during the displacement reaction, allowing for accurate observations and comparisons.
When iron nails are immersed in copper sulphate solution for 20 minutes, the following observations are made:
The iron nail becomes brownish in color after being dipped in the copper sulphate solution due to the displacement reaction that occurs between iron and copper. The reaction can be represented as follows:
Fe(s) + CuSO4(aq) → FeSO4(aq) + Cu(s)
Here, the iron (Fe) from the nail displaces the copper (Cu) from the copper sulphate solution, resulting in the formation of iron sulphate (FeSO4) and solid copper (Cu). The brownish color observed on the iron nail is due to the formation of iron sulphate.
After the activity, the changes observed in the intensity of the blue color of the copper sulphate solution in test tubes (A) and (B) are as follows:
The iron nails dipped in the copper sulphate solution develop a brownish color, while the iron nail kept aside retains its original color. From this comparison, it can be inferred that the brownish color on the iron nails is due to the formation of iron sulphate as a result of the displacement reaction between iron and copper. The absence of this color change in the iron nail kept aside confirms that the brownish color is specifically caused by the reaction with the copper sulphate solution.
Fe(s) + CuSO4(aq) → FeSO4(aq) + Cu(s)
The products formed in the displacement reaction between iron and copper sulphate are iron sulphate (FeSO4) in the aqueous form and solid copper (Cu).
A displacement reaction is a chemical reaction in which one element displaces or replaces another element from its compound. In the text, examples of other displacement reactions mentioned are:
Zinc and lead can displace copper from its compounds because they are more reactive metals than copper. According to the reactivity series of metals, zinc and lead are higher in reactivity compared to copper. In a displacement reaction, a more reactive metal can replace a less reactive metal from its compound. Hence, when zinc or lead is added to a copper compound, such as copper sulphate or copper chloride, the zinc or lead atoms will displace the copper atoms, resulting in the formation of zinc or lead compounds and solid copper.
Based on their ability to undergo displacement reactions, zinc and lead are more reactive than copper. This is because zinc and lead can displace copper from its compounds in displacement reactions, as mentioned in the previous question. Copper, on the other hand, is less reactive and is displaced by both zinc and lead from their respective compounds. Reactivity series of metals places zinc and lead above copper, indicating their higher reactivity.
Displacement reactions hold significant importance in various industrial processes. Some of their applications are:
Displacement reactions are used to extract metals from their ores by employing a more reactive metal to displace the desired metal from its compound. The metal ore, usually in the form of its oxide or sulphide, is heated with the more reactive metal. The more reactive metal displaces the less reactive metal from its compound, resulting in the formation of the desired metal and a compound of the more reactive metal.
A real-life application of displacement reactions is the galvanization process. Galvanization is used to protect iron or steel from corrosion by applying a layer of zinc onto their surface. The process involves a displacement reaction where the more reactive zinc displaces iron from the surface and forms a protective layer of zinc on the metal. The working principle is as follows: The iron or steel object is first cleaned and treated to ensure a clean surface. It is then dipped into a bath of molten zinc or exposed to zinc vapors. The zinc, being more reactive, displaces the iron from the surface and forms a layer of zinc. This layer acts as a barrier, protecting the underlying iron or steel from corrosion by preventing direct contact with the corrosive environment.
The reactivity series of metals is a list that arranges metals in order of their reactivity. It helps in predicting the outcome of displacement reactions by determining which metal can displace another metal from its compound. According to the series, a more reactive metal can displace a less reactive metal from its compound. By referring to the reactivity series, we can determine whether a displacement reaction will occur between two metals and predict the products formed. The metal higher in the series will displace the metal lower in the series from its compound. This knowledge allows us to understand the feasibility and outcome of various displacement reactions involving different metals.
The steps involved in Activity 1.10 are as follows:
The two solutions used in Activity 1.10 are sodium sulphate solution (Na2SO4) and barium chloride solution (BaCl2). Approximately 3 mL of each solution is taken.
When the sodium sulphate solution and barium chloride solution are mixed, a white substance is formed. This white substance is insoluble in water and is known as a precipitate. The observation of the white precipitate formation indicates the occurrence of a double displacement reaction: Na2SO4(aq) + BaCl2(aq) → BaSO4(s) + 2NaCl(aq).
A precipitate is a solid substance that forms during a chemical reaction when two aqueous solutions are mixed. It is insoluble in the solvent (usually water) and separates out as a solid. In precipitation reactions, a precipitate is formed as a result of the exchange of ions between the reactants.
The balanced chemical equation for the double displacement reaction between sodium sulphate (Na2SO4) and barium chloride (BaCl2) is: Na2SO4(aq) + BaCl2(aq) → BaSO4(s) + 2NaCl(aq)
The products formed in the double displacement reaction between sodium sulphate and barium chloride are barium sulphate (BaSO4) in the solid form and sodium chloride (NaCl) in the aqueous form:
Ba2+(aq) + SO42-(aq) → BaSO4(s)
2Na+(aq) + 2Cl-(aq) → 2NaCl(aq)
The white precipitate of BaSO4 is formed by the reaction between the sulphate ions (SO42-) from sodium sulphate and the barium ions (Ba2+) from barium chloride. The reaction can be represented as follows:
Ba2+(aq) + SO42-(aq) → BaSO4(s)
In the reaction between sodium sulphate and barium chloride, sodium chloride (NaCl) is one of the products. It remains in the solution as it is soluble in water. Sodium chloride does not contribute to the formation of the white precipitate of BaSO4.
A double displacement reaction is a chemical reaction in which two compounds exchange ions to form two new compounds. It can be represented as AB + CD → AD + CB, where A, B, C, and D represent different elements or groups.
An example of a double displacement reaction mentioned in the text is the reaction between sodium sulphate (Na2SO4) and barium chloride (BaCl2), which produces barium sulphate (BaSO4) and sodium chloride (NaCl):
Na2SO4(aq) + BaCl2(aq) → BaSO4(s) + 2NaCl(aq)
Double displacement reactions are often called precipitation reactions because one of the products formed is a precipitate, which is an insoluble solid. During the reaction, the exchange of ions between the reactants leads to the formation of an insoluble substance (precipitate) that separates from the solution as a solid.
For a double displacement reaction to occur:
One real-life application of double displacement reactions is the production of soap. The saponification process involves a double displacement reaction between a fatty acid (such as stearic acid) and a strong base (such as sodium hydroxide). This reaction produces soap (a sodium salt of the fatty acid) and glycerol. The soap formed in this reaction has surfactant properties, allowing it to dissolve in water and remove dirt and oil from surfaces.
Ionic exchange in double displacement reactions involves the swapping of ions between two compounds. The cations and anions of the reactants exchange places, resulting in the formation of new compounds. The specific combination of cations and anions determines the identity of the products formed in the reaction.
The reactivity series of metals can help predict the outcome of double displacement reactions involving metal compounds. If a more reactive metal is present in one compound, it can displace a less reactive metal from another compound. By referring to the reactivity series, one can determine the relative reactivity of the metals involved and predict which metal will displace the other in the reaction.
Solubility refers to the ability of a substance to dissolve in a solvent, typically water. In the context of double displacement reactions, solubility plays a crucial role in the formation of a precipitate. When two aqueous solutions are mixed, the ions present in the solutions interact. If the product formed is insoluble in water, it will separate out as a solid precipitate.
Balancing chemical equations is important in double displacement reactions to ensure the conservation of mass and charge. An example from the given paragraph is the balanced equation for the reaction between sodium sulphate (Na2SO4) and barium chloride (BaCl2):
Na2SO4(aq) + BaCl2(aq) → BaSO4(s) + 2NaCl(aq)
By balancing the equation, we ensure that the number of atoms and charges on both sides of the equation is equal.
Ions play a crucial role in double displacement reactions as they determine the products formed. When two compounds containing different cations and anions are mixed, the ions undergo an exchange, leading to the formation of new compounds. The specific combination of cations and anions determines the identity of the products formed in the reaction.
To confirm the presence of a precipitate in a double displacement reaction, one can perform a simple observation test. After mixing the two solutions, observe whether a solid substance forms that does not dissolve in water. This solid substance indicates the formation of a precipitate.
Double displacement reactions involve the exchange of ions between two compounds, resulting in the formation of two new compounds. In contrast, single displacement reactions involve the displacement of one element by another element in a compound. An example of a double displacement reaction is the reaction between sodium sulphate (Na2SO4) and barium chloride (BaCl2), as mentioned earlier.
An example of a single displacement reaction is the reaction between zinc (Zn) and hydrochloric acid (HCl):
Zn(s) + 2HCl(aq) → ZnCl2(aq) + H2(g)
The reaction type observed in Activity 1.10 is a double displacement reaction. The balanced chemical equation for the reaction is:
Na2SO4(aq) + BaCl2(aq) → BaSO4(s) + 2NaCl(aq)
The formation of the white precipitate, BaSO4, occurs due to the exchange of ions between the reactants. Specifically, the sulfate ions (SO42-) from sodium sulphate react with the barium ions (Ba2+) from barium chloride to form the insoluble compound, barium sulfate (BaSO4). Sodium chloride (NaCl) is also formed but remains dissolved in the solution. This reaction is a double displacement reaction, where the cations and anions of the reactants exchange partners to form new compounds.
When a china dish containing copper powder is heated, the observation made is that the surface of the copper powder becomes coated with black copper(II) oxide.
The surface of the copper powder becomes coated with black copper(II) oxide when heated because oxygen from the air combines with the copper atoms to form copper(II) oxide. The chemical equation for this reaction is:
2Cu + O₂ → Heat → 2CuO
The balanced chemical equation for the reaction between copper and oxygen, forming copper(II) oxide, is:
2Cu + O₂ → Heat → 2CuO
When hydrogen gas is passed over the black coating of copper(II) oxide on the copper powder surface, the black coating turns brown as the reverse reaction takes place. The reverse reaction is the reduction of copper(II) oxide by hydrogen gas to produce copper metal and water. The balanced chemical equation for this reverse reaction is:
CuO + H₂ → Heat → Cu + H₂O
The balanced chemical equation for the reverse reaction between copper(II) oxide and hydrogen, forming copper and water, is:
CuO + H₂ → Heat → Cu + H₂O
Oxidation is defined as the process in which a substance gains oxygen during a reaction, while reduction is defined as the process in which a substance loses oxygen during a reaction.
In the reaction between copper(II) oxide and hydrogen, copper(II) oxide is being reduced as it loses oxygen, and hydrogen is being oxidized as it gains oxygen. The balanced chemical equation for this reaction is:
CuO + H₂ → Heat → Cu + H₂O
Oxidation-reduction reactions, or redox reactions, are chemical reactions in which there is a transfer of electrons between reactants. These reactions involve the simultaneous occurrence of oxidation (loss of electrons) and reduction (gain of electrons). The key characteristics of redox reactions are the exchange of electrons and changes in oxidation states of the participating elements.
Example 1: ZnO + C → Zn + CO
In this reaction, carbon (C) is oxidized to carbon monoxide (CO), and zinc oxide (ZnO) is reduced to zinc (Zn).
Example 2: MnO₂ + 4HCl → MnCl₂ + 2H₂O + Cl₂
In this reaction, hydrochloric acid (HCl) is oxidized to chlorine gas (Cl₂), and manganese dioxide (MnO₂) is reduced to manganese chloride (MnCl₂).
In the reaction between zinc oxide and carbon, carbon (C) is oxidized to carbon monoxide (CO) as it gains oxygen, and zinc oxide (ZnO) is reduced to zinc (Zn) as it loses oxygen.
In the reaction between manganese dioxide and hydrochloric acid, hydrochloric acid (HCl) is oxidized to chlorine gas (Cl₂) as it loses hydrogen, and manganese dioxide (MnO₂) is reduced to manganese chloride (MnCl₂) as it gains hydrogen.
If a substance gains oxygen during a reaction, it is oxidized. If a substance loses oxygen during a reaction, it is reduced. Similarly, if a substance gains hydrogen during a reaction, it is reduced, and if it loses hydrogen, it is oxidized.
Redox reactions have significant importance in everyday life and various industrial processes. Some examples include:
Redox reactions play a crucial role in the corrosion of metals, such as the process of rusting in iron. In the presence of moisture and oxygen, iron undergoes oxidation to form iron(III) oxide (rust). The reaction can be represented as follows:
4Fe + 3O₂ + 6H₂O → 4Fe(OH)₃ (formation of hydrated iron(III) oxide, rust)
In this reaction, iron is oxidized as it loses electrons to form iron(III) ions. Oxygen is reduced as it gains electrons to form hydroxide ions. The overall process of rusting involves the continuous oxidation and reduction of iron, leading to the degradation of the metal.
A real-life application of a redox reaction is the process of electrolysis. Electrolysis involves the use of an electric current to drive a non-spontaneous redox reaction. One important application of electrolysis is the production of various metals, such as aluminum, by extracting them from their compounds. The process allows for the reduction of metal ions at the cathode and the oxidation of other substances at the anode. Electrolysis has great importance in industries, such as metal refining, electroplating, and the production of chemicals.
Oxidation reactions involve the gain of oxygen or the loss of hydrogen by a substance, while reduction reactions involve the loss of oxygen or the gain of hydrogen by a substance. Oxidation reactions result in an increase in the oxidation state of the oxidized substance, while reduction reactions lead to a decrease in the oxidation state of the reduced substance.
Corrosion is the process by which a metal is gradually destroyed or deteriorated by the action of substances around it, such as moisture and acids. It leads to the formation of undesirable products on the surface of the metal. Examples of metals that undergo corrosion include iron, copper, and silver.
The common name for the process of rusting of iron is oxidation.
When iron articles undergo corrosion, they undergo a physical change wherein they become coated with a reddish-brown powder. This coating is known as rust.
Moisture and acids play a crucial role in the corrosion process. Moisture provides the necessary medium for the electrochemical reactions to occur, while acids can accelerate the corrosion process by acting as electrolytes and promoting the flow of electrons.
The coating formed on copper due to corrosion is green, while the coating formed on silver is black.
Objects such as car bodies, bridges, iron railings, ships, and various metallic structures made of iron are prone to corrosion.
The corrosion of iron is considered a serious problem due to the significant economic impact it has. The replacement of damaged iron structures and objects costs an enormous amount of money every year.
The economic impact of corrosion is substantial as a considerable amount of money is spent annually on replacing damaged iron structures and objects. The cost includes not only the replacement materials but also the labor and resources required for the replacement process.
When fats and oils are oxidized, they undergo a chemical reaction with oxygen in the air, resulting in rancidity. The oxidation reaction can be represented as follows:
Fat/Oil + O2 → Rancid product
During this process, the smell and taste of the fats and oils change, becoming unpleasant and often foul.
Antioxidants are substances added to foods containing fats and oils to prevent oxidation. They work by inhibiting the oxidation reaction, thus delaying or preventing rancidity. Antioxidants react with free radicals or other reactive species, interrupting the chain reactions responsible for the oxidation process. Examples of common antioxidants used in food preservation include ascorbic acid (vitamin C), tocopherols (vitamin E), and butylated hydroxyanisole (BHA).
Storing food in air-tight containers helps slow down oxidation by minimizing the contact between the food and atmospheric oxygen. When the food is sealed in an air-tight container, the availability of oxygen is reduced, limiting the oxidation process. This helps preserve the quality of the fats and oils and extends the shelf life of the food.
The purpose of flushing bags of chips with gas, such as nitrogen, is to prevent the chips from getting oxidized. Nitrogen gas is inert and does not react with the chips or the fats and oils present in them. By displacing the oxygen inside the bag, the nitrogen gas creates an oxygen-free environment, which significantly reduces the oxidation of the chips. This helps maintain the freshness, taste, and crispness of the chips for a longer period.
Rancidity is the process of fats and oils undergoing oxidation, resulting in changes in their smell and taste. It occurs due to the reaction between the unsaturated fatty acids present in the fats and oils and atmospheric oxygen. This oxidation process can be accelerated by factors such as exposure to light, heat, and moisture. Rancid fats and oils not only develop unpleasant odors and flavors but also lose their nutritional value. To prevent rancidity, proper storage conditions, such as air-tight containers and the addition of antioxidants, are essential.
Class 10 Science Chapter 1 - Chemical Reactions and Equations Important Questions and Answers
Class 10 CBSE Important Questions and Answers Chapter 1 - Chemical Reactions and Equations
Class 10 NCERT Chapter 1 - Chemical Reactions and Equations AJs Chalo Seekhen Class 10 CBSE Important Questions and Answers Chapter 1 - Chemical Reactions and Equations ajs notes history chapter 1 ajs class 10 chapter 1 imp questions
Dedicated team provides prompt assistance and individual guidance.
Engaging visuals enhance understanding of complex concepts.
Engaging visuals enhance understanding of complex concepts.
Assess understanding and track progress through topic-specific tests
Launch your Graphy
