NCERT Solutions For Class 10 Science Chapter 1 Chemical Reactions And Equations - Cbsestudyguru

NCERT Solutions For Class 10 Science Chapter 1 Chemical reactions and equations

Class 10 Science Chapter 1 Chemical reactions and equations

1. Exercise Questions
2. Intext Questions

NCERT Solutions For Class 10 Science Chapter 1 Chemical Reactions And Equations, in this step-by-step answer guide. In some of State Boards and CBSE schools, students are taught thru NCERT books. As the chapter comes to an end, students are requested few questions in an exercising to evaluate their expertise of the chapter. Students regularly want guidance managing those NCERT Solutions.

It’s most effective natural to get stuck withinside the exercises while solving them so that you can assist students score higher marks, we’ve provided step by step NCERT answers for all exercises of Class ten Science Chemical Reactions And Equations so you can be looking for assist from them.

Students should solve those exercises carefully as questions withinside the final exams are requested from those, so these exercises immediately have an impact on students’ final score. Find all NCERT Solutions for Class ten Science Chemical Reactions And Equations below and prepare in your tests easily.

NCERT Solutions For Class 10 Science Chapter 1 Chemical reactions and equations

Class 10 Science Chapter 1 Chemical reactions and equations

EXERCISE QUESTIONS

 

Q. 1. Which of the statements about the reaction below are incorrect ?

2PbO ( s ) + C ( s ) → 2Pb ( s ) + CO₂ ( g )

( i ) Lead is getting reduced .

( ii ) Carbon dioxide is getting oxidised .

( iii ) Carbon is getting oxidised .

( iv ) Lead oxide is getting reduced .

( a ) ( i ) and ( ii )

( b ) ( i ) and ( iii )

( c ) ( i ) , ( ii ) and ( iii )

( d ) All

Ans . Correct option : ( a )

Explanation : Lead oxide is getting reduced to lead and Carbon is getting oxidised .

Q. 2. Fe₂O3 + 2Al → Al₂O3 + 2Fe

The above reaction is an example of a :

( a ) combination reaction .

( b ) double displacement reaction .

( c ) decomposition reaction .

( d ) displacement reaction

Ans . Correct option : ( d )

Explanation : The given reaction is an example of a displacement reaction .

Q. 3 . What happens when dilute hydrochloric acid is added to iron filings ? Tick the correct answer .

( a ) Hydrogen gas and iron chloride are produced .

( b ) Chlorine gas and iron hydroxide are produced .

( c ) No reaction takes place .

( d ) Iron salt and water are produced .

Ans . Correct option : ( a )

Explanation : When dilute hydrochloric acid is added to iron filings , hydrogen gas and iron chloride are produced . The reaction is as follows :

Fe ( s ) + 2HCl ( aq ) → FeCl₂ ( aq ) + H₂

Q. 4. What is a balanced chemical equation ? Why should chemical equations be balanced ?

Ans . The chemical equation in which the number of atoms of each element on both the sides is equal is called the balanced equation . A chemical equation should be balanced because there is no loss or gain of any matter during a chemical reaction , i.e. , the law of conservation of mass must hold good for the reaction .

Q. 5. Translate the following statements into chemical equations and then balance them .

( a ) Hydrogen gas combines with nitrogen to form ammonia .

( b ) Hydrogen sulphide gas burns in air to give water and sulphur dioxide .

( c ) Barium chloride reacts with aluminium sulphate to give aluminium chloride and a precipitate of barium sulphate .

( d ) Potassium metal reacts with water to give potassium hydroxide and hydrogen gas .

Ans . ( a ) 3H₂ ( g ) + N₂ ( g ) → 2NH3 ( g )

( b ) 2H₂ S ( g ) + 3O₂ ( g ) → 2H₂O ( l ) + 2SO₂ ( g )

( c ) 3BaCl₂ ( aq ) + Al₂ ( SO4 )3 ( aq ) → 2AlCl3 ( aq ) + 3BaSO4 ( ppt )

( d ) 2K ( s ) + 2H₂O ( l ) → 2KOH ( aq ) + H₂ ( g )

Q. 6. Balance the following chemical equations .

( a ) HNO3 + Ca ( OH )2 → Ca ( NO3 )2 + H₂O

( b ) NaOH + H₂SO4 → Na₂SO4 + H₂O

( c ) NaCl + AgNO3 → AgCl + NaNO3

( d ) BaCl₂ + H₂SO4 → BaSO4 + HCI

Ans . ( a ) 2HNO3 + Ca ( OH )2 → Ca ( NO3 )2 + 2H₂O

( b ) 2NaOH + H₂SO4 → Na₂SO4 + 2H₂O

( c ) NaCl + AgNO3 → AgCl + NaNO3

( d ) BaCl₂ + H₂SO4 → BaSO4 + 2HCl

Q. 7. Write the balanced chemical equations for the following reactions .

( a ) Calcium hydroxide + Carbon dioxide → Calcium carbonate + Water

( b ) Zinc + Silver nitrate → Zinc nitrate + Silver

( c ) Aluminium + Copper chloride → Aluminium chloride + Copper

( d ) Barium chloride + Potassium sulphate → Barium sulphate + Potassium chloride

Ans . ( a ) Ca ( OH )2 + CO₂ → CaCO3 + H₂O

( b ) Zn + 2AgNO3 → Zn ( NO3 )2 + 2Ag

( c ) 2Al + 3CuCl₂ → 2AlCl3 + 3Cu

( d ) BaCl2 + K2SO4 → BaSO4 + 2KCl

Q. 8. Write the balanced chemical equations for the following and identify the type of reaction in each case .

( a ) Potassium bromide ( aq ) + Barium iodide ( aq ) → Potassium iodide ( aq ) + Barium bromide ( s )

( b ) Zinc carbonate ( s ) → Zinc oxide ( s ) + Carbon dioxide ( g )

( c ) Hydrogen ( g ) + Chlorine ( g ) → Hydrogen chloride ( g )

( d ) Magnesium ( s ) + Hydrochloric acid ( aq ) → Magnesium chloride ( aq ) + Hydrogen ( g )

Ans . ( a ) 2KBr ( aq ) + BaI₂ ( aq ) → 2Kl ( aq ) + BaBr₂ ( s ) ; Double displacement reaction

( b ) ZnCO3 ( s ) → ZnO ( s ) + CO₂ ( g ) ; Decomposition reaction

( c ) H₂ ( g ) + Cl₂ ( g ) → 2HCl ( g ) ; Combination reaction

( d ) Mg ( s ) + 2HCl ( aq ) → MgCl₂ ( aq ) + H₂ ( g ) ; Displacement reaction

Q. 9. What does one mean by exothermic and endothermic reactions ? Give examples .

Ans . Exothermic reaction : Reactions in which energy is released in the form of heat , light , or sound along with the formation of products are called exothermic reactions .

Examples :

Mixture of sodium and chlorine to yield table salt :

2Na + Cl₂ → 2NaCl + 411 kJ of energy

Burning of natural gas :

CH₂ ( g ) + 2O₂ ( g ) → CO₂ ( g ) + 2H₂O ( g )

We get energy to stay alive from the food we eat . During digestion , food is broken down into simpler substances . For example , rice , potatoes and bread contain carbohydrates . These carbohydrates are broken down to form glucose . This glucose combines with oxygen in the cells of our body and provides energy . The special name of this reaction is respiration .

C6H₁2O6 ( aq ) + 6O₂ ( aq ) → 6CO₂ ( aq ) + 6H₂O ( l ) + ( Glucose ) Energy

The decomposition of vegetable matter into compost is also an example of an exothermic reaction .

Endothermic reaction : Reactions in which energy is absorbed or required energy either in the form of heat , light or electricity for breaking down the reactants are known as endothermic reactions .

Example :

In the process of photosynthesis , plants use the energy from the sun to convert carbon dioxide and water to glucose and oxygen .

A picture containing textDescription automatically generated

Q. 10 . Why is respiration considered an exothermic reaction ? Explain .

Ans . Energy is required to support life . Energy in our body is obtained from the food we eat . During digestion , large molecules of food are broken down into simpler substances such as glucose . Glucose combines with oxygen in the cells and provides energy . The special name of this combustion reaction is respiration . Since energy is released in the whole process , it is an exothermic process .

C6H₁2O6 ( aq ) + 6O₂ ( g ) → 6CO₂ ( g ) + 6H₂O ( l ) + Energy

Q. 11. Why are decomposition reactions called the opposite of combination reactions ? Write equations for these reactions .

Ans . Decomposition reactions are those in which a compound breaks down to form two or more substances . These reactions require a source of energy to proceed . Thus , they are the exact opposite of combination reactions in which two or more substances combine to give a new substance with the release of energy .

Decomposition reaction :

AB + Energy → A + B

TextDescription automatically generated with medium confidence

Combination reaction :

A + B → AB + Energy

2CO + O₂ → 2CO₂ + Energy

Q. 12. Write one equation , each for decomposition reactions , where energy is supplied in the form of heat , light or electricity .

Ans . ( 1 ) Thermal decomposition :

A picture containing diagramDescription automatically generated

( 2 ) Decomposition by light :

TextDescription automatically generated with medium confidence

( 3 ) Decomposition by electricity :

TextDescription automatically generated with medium confidence

Q. 13. What is the difference between displacement and double displacement reactions ? Write equations for these reactions .

Ans . Difference between displacement and double displacement reactions are given ahead :

TableDescription automatically generated

Q. 14. In the refining of silver , the recovery of silver from silver nitrate solution involved displacement by copper metal . Write down the reaction involved .

Ans . 2AgNO3 ( aq ) + Cu ( s ) → Cu ( NO3 )2 ( aq ) + 2Ag ( s )

Silver nitrate Copper Copper nitrate Silver

Q. 15. What do you mean by a precipitation reaction ? Explain by giving examples .

Ans . A reaction in which an insoluble solid ( called precipitate ) is formed is called a precipitation reaction . The salts formed are precipitates and are the products of precipitation reaction . The precipitation reactions are the double displacement reactions involving the production of a solid form residue called the precipitate . The reaction also occurs when two or more solutions with different salts are combined , resulting in the formation of insoluble salts that precipitates out of the solution .

Examples :

( i ) Na2SO4 ( aq ) + BaCl2 ( aq ) → BaSO4 ( s ) + 2NaCl ( aq )

The white precipitate of BaSO4 is formed by the reaction of SO4² and Ba²+ . The other product formed is sodium chloride which remains in the solution .

( ii ) Na₂CO3 ( aq ) + CaCl₂ ( aq ) → CaCO3 ( s ) + 2NaCl ( aq )

In this reaction , calcium carbonate is obtained as a precipitate . Hence , it is a precipitation reaction

( iii ) AgNO3 ( aq ) + KCl ( aq ) → AgCl ( ppt . ) + KNO3 ( aq )

In this reaction , a white precipitate called as silver chloride or AgCl is formed which is in a solid state .

Q. 16. Explain the following in terms of gain or loss of oxygen with two examples each .

( a ) Oxidation ( b ) Reduction

Ans . ( a ) Oxidation is the gain of oxygen .

For example :

TextDescription automatically generated

In equation ( i ) , CO₂ is reduced to CO and in equation ( ii ) , CuO is reduced to Cu .

Q. 17. A shiny brown – coloured element ‘ X ‘ on heating in air becomes black in colour . Name the element ‘ X ‘ and the black coloured compound formed .

Ans . X ‘ is copper ( Cu ) and the black – coloured compound formed is copper oxide ( CuO ) . The equation of the reaction involved on heating copper is given below .

A picture containing graphical user interfaceDescription automatically generated

Q. 18. Why do we apply paint on iron articles ?

Ans . Iron articles are painted because it prevents them from rusting . When painted , the contact of iron articles from moisture and air is cut off . Hence , rusting is prevented . Their presence is essential for rusting to take place .

Q. 19. Oil and fat containing food items are flushed with nitrogen . Why ?

Ans . Nitrogen is an inert gas and does not easily react with these substances . On the other hand , oxygen reacts with food substances and makes them rancid . Thus , bags used in packing food items are flushed with nitrogen gas to remove oxygen inside the pack . When oxygen is not present inside the pack , rancidity of oil and fat containing food items is avoided .

Q. 20. Explain the following terms with one example each .

( a ) Corrosion ( b ) Rancidity

Ans . ( a ) Corrosion : A process where materials , usually metals , deteriorate on interaction with air , moisture , chemicals , etc. , as a result of chemical reactions between them is known as corrosion .

The black coating on silver and the green coating on copper are other examples of corrosion . Corrosion causes damage to car bodies , bridges , iron railings , ships and to all objects made of metals , especially those of iron . Corrosion of iron is a serious problem .

Corrosion makes the metals scaly and decreases their envisioned usage period . The strength , appearance and permeability are also degraded . A considerable amount of damage is done by corrosion every year , which includes damaging of cars , grills , buses , railings , sinking of ships , falling off bridges , deterioration of statues , etc.

For example , iron , in the presence of moisture , reacts with oxygen to form hydrated iron oxide .

4Fe + 3O2 + nH2O → 2Fe2O3.nH2O

This hydrated iron oxide is rust .

( b ) Rancidity : The process of oxidation of fats and oils that can be easily noticed by the change in taste and smell is known as rancidity . It spoils food materials that makes difficult consumption .

For example , the taste and smell of butter changes when kept for long .

Rancidity can be avoided by :

( i ) Storing food in air tight containers .

( ii ) Storing food in refrigerators or at very low temperatures .

( iii ) Adding antioxidants .

( iv ) Storing food in an environment of nitrogen .

INTEXT QUESTIONS

Page 6

Q. 1. Why should a magnesium ribbon be cleaned before burning in air ? [ NCERT Q. 1 , Page 6 ]

Ans . Magnesium is a very reactive metal like Na , Ca , etc .. When exposed to air it reacts with oxygen to form a layer of magnesium oxide ( MgO ) on its surface .

2Mg + O₂ → 2MgO

This layer of magnesium oxide is pretty stable and prevents additional reaction of magnesium with oxygen . The magnesium ribbon is cleaned by sand paper to remove this layer so that the underlying metal can be used for the reaction .

Q. 2. Write the balanced equation for the following chemical reactions .

( i ) Hydrogen + Chlorine → Hydrogen chloride

( ii ) Barium chloride + Aluminium sulphate → Barium sulphate + Aluminium chloride

( iii ) Sodium + Water Sodium hydroxide + Hydrogen [ NCERT Q. 2 , Page 6 ]

Ans . ( i ) H₂ + Cl₂ → 2HCI

( ii ) 3BaCl₂ + Al₂ ( SO4 )3 → 3BaSO4 + 2AICI3

( iii ) 2Na + 2H₂O → 2NaOH + H₂

Q. 3. Write a balanced chemical equation with state symbols for the following reactions .

( i ) Solutions of barium chloride and sodium sulphate in water react to give insoluble barium sulphate and the solution of sodium chloride .

( ii ) Sodium hydroxide solution ( in water ) reacts with hydrochloric acid solution ( in water ) to produce sodium chloride solution and water . [ NCERT Q. 3 , Page 6 ]

Ans . ( i ) BaCl₂ ( aq ) + Na₂SO4 ( aq ) → BaSO4 ( s ) + 2NaCl ( aq )

( ii ) NaOH ( aq ) + HCl ( aq ) → NaCl ( aq ) + H₂O ( l )

Page 10

Q. 4. A solution of a substance ‘ X ‘ is used for white washing .

( i ) Name the substance ‘ X ‘ and write its formula .

( ii ) Write the reaction of the substance ‘ X ‘ named in ( i ) above with water . [ NCERT Q. 1 , Page 10 ]

Ans . ( i ) The substance ‘ X ‘ is calcium oxide . Its chemical formula is CaO .

( ii ) Calcium oxide reacts vigorously with water to form calcium hydroxide ( slaked lime )

CaO ( s ) + H2O ( l ) → Ca ( OH ) ₂ ( aq )

Calcium oxide or Calcium Hydroxide

Quicklime or Slaked lime

Q. 5. Why is the amount of gas collected in one of the test tubes during electrolysis water , double of the amount collected in the other ? Name this gas . [ NCERT Q. 2 , Page 10 ]

Ans . During the electrolysis of water , hydrogen and oxygen get separated by the electricity . Water ( H₂O ) contains two parts hydrogen and one part of oxygen . Since hydrogen goes to one test tube and oxygen goes to another , the amount of gas collected in one of the test tubes is double of the amount collected in the other .

Page 13

Q. 6. Why does the colour of copper sulphate solution change when an iron nail is dipped in it ? [ NCERT Q. 1 , Page 13 ]

Ans . When an iron nail is dipped in a copper sulphate solution , iron displaces copper from copper sulphate solution forming iron sulphate , which is green in colour . This is because iron is more reactive than copper .

CuSO4 + Fe → FeSO4 + Cu .

Therefore , the blue colour of copper sulphate solution fades and green colour appears .

Q.7 . Give an example of a double displacement reaction other than formation of barium sulphate and sodium chloride . [ NCERT Q. 2 , Page 13 ]

Ans . Sodium carbonate reacts with calcium chloride to form calcium carbonate and sodium chloride .

Na₂CO3 + CaCl₂ → CaCO3 + 2NaCl

In this reaction , sodium carbonate and calcium chloride exchange ions to form two new compounds . Hence , it is a double displacement reaction .

Q. 8. Identify the substances that are oxidised and the substances that are reduced in the following reactions .

( i ) 4Na ( s ) + O₂ ( g ) → 2Na₂O ( s )

( ii ) CuO ( s ) + H₂ ( g ) → Cu ( s ) + H₂O ( l ) [ NCERT Q.3 , Page 13 ]

Ans . ( i ) Sodium ( Na ) is oxidised as it gains oxygen and oxygen gets reduced .

( ii ) Copper oxide ( CuO ) is reduced to copper ( Cu ) while hydrogen ( H₂ ) gets oxidised to water ( H₂O ) .

 

Benefits of NCERT Solutions

NCERT’s Class 10 solution contains extremely important points, and for each chapter, each concept has been simplified to make it easier to remember and increase your chances of achieving excellent exam results. Exam Preparation References Here are some tips on how these solutions can help you prepare for the exam.

  1. This helps students solve many of the problems in each chapter and encourages them to make their concepts more meaningful.
  2. NCERT Solutions for Class 10 solutions encourage you to update your knowledge and refine your concepts so that you can get good results in the exam.
  3. These solutions are the best exam materials, allowing you to learn more about your week and your strengths. To get good results in the exam, it is important to overcome your weaknesses.
  4. Most of the questions in the exam are formulated in a similar way to NCERT textbooks. Therefore, students should review the solutions in each chapter in order to better understand the topic.
  5. It is free of cost.

Tips & Strategies for Class 10 Exam Preparation

  1. Plan your course and syllabus and make time for revision
  2. Please refer to the NCERT solution available on the cbsestudyguru website to clarify your concepts every time you prepare for the exam.
  3. Use the cbsestudyguru learning app to start learning to successfully pass the exam. Provide complete teaching materials, including resolved and unresolved tasks.
  4. It is important to clear all your doubts before the exam with your teachers or Alex (an Al study Bot). 
  5. When you read or study a chapter, write down algorithm formulas, theorems, etc., and review them quickly before the exam.
  6. Practice an ample number of question papers to make your concepts stronger. 
  7. Take rest and a proper meal.  Don’t stress too much. 

Why opt for cbsestudyguru NCERT Solutions for Class 10 ? 

  • cbsestudyguru provide NCERT Solutions for all subjects at your fingertips.
  • These solutions are designed by subject matter experts and provide solutions to every NCERT textbook questions. 
  • cbsestudyguru especially focuses on making learning interactive, effective and for all classes.
  • We provide free NCERT Solutions for class 10 and all other classes.

Leave a Comment