CBSE Class 10 Science Chemical Reactions and Equations MCQs

Question : What happens when dilute hydrochloric acid is added to iron filling? 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

Answer :  A

Question : A student added dilute HCl to a test tube containing zinc granules and made following observations :
(a) the zinc surface became dull and black
(b) a gas evolved which burnt with a pop sound
(c) the solution remained colourless
(d) the solution becomes green in colour

Answer :  B

Question : The reaction of H2 gas with oxygen gas to form water is an example of
(a) combination reaction
(b) redox reaction
(c) exothermic reaction
(d) all of these reactions

Answer :  A

Question : The condition produced by aerial oxidation of fats and oils in foods marked by unpleasant smell and taste is called:
(a) Antioxidation
(b) Reduction
(c) Rancidity
(d) Corrosion

Answer :  C

Question : The blue flame in the below image represents the burning of which metal?
(a) Iron
(b) Copper
(c) Sodium
(d) All metal burn to give a blue flame

Answer :  B

Question : In a context of redox reactions, the removal of hydrogen from a substance is known as
(a) Oxidation
(b) Dehydration
(c) Reduction
(d) Dehydrogenation

Answer :  A

Question :  Dissolving suger is an example of
(a) Physical change
(b) Chemical change
(c) Redox Reaction
(d) None of these.

Answer :  A

Question. CuSO₄ + Zn → Cu + ZnSO₄ This reaction is an example of a: 
(a) Combination reaction. 
(b) Double displacement reaction. 
(c) Decomposition reaction. 
(d) Displacement reaction.

Answer : D

Question. What happens when dilute Sulphuric acid is added to Zn granules? Tick the correct answer.
(a) Hydrogen gas and Zinc chloride are produced) 
(b) Chlorine gas and Zinc hydroxide are produced) 
(c) No reaction takes place. 
(d) Zinc salt and water are produced)

Answer : A

Question. Translate the following statements into chemical equations and then balance it. 
Barium chloride reacts with aluminium sulphate to give aluminium chloride and a precipitate of barium sulphate. 
(a) BaCl₂ + Al₂(SO₄)₃ → AlCl₃ + BaSO₄ 
(b) 3BaCl₂ + Al₂(SO₄)₃ →2 AlCl₃ +3BaSO₄ 
(c) BaCl₂ + AlSO₄ → AlCl₂ + BaSO₄ 
(d) BaCl₃ + Al(SO₄)₃ → AlCl₃ + Ba(SO₄)₃

Answer : B

Question. Identify the type of reaction in each case. 
Zinc carbonate(s) → Zinc oxide(s) + Carbon dioxide(g)
Hydrogen(g) + Chlorine(g) → Hydrogen chloride(g) 
(a) Combination, Decomposition 
(b) Double displacement, Combination 
(c) Decomposition, Combination 
(d) Displacement, Decomposition

Answer : C

Question. The balancing of chemical equations is in accordance with:
(a) Law of combining volumes
(b) Law of constant proportions
(c) Law of conservation of mass
(d) Both b and c

Answer : D

Question. Which of the statements about the reaction below are incorrect? Fe₂O₃(s) + 3CO(g) →2Fe(s) +3CO₂(g)
(a) Iron is getting reduced)
(b) Carbon dioxide is getting oxidised)
(c) Carbon monoxide is getting oxidised)
(d) Iron oxide is getting reduced)
i. a & b
ii. a & c
iii. c & d
iv. all

Answer : C

Question. What type of reaction is respiration
(a) Exothermic
(b) Endothermic
(c) Reduction reaction
(d) Combination reaction

Answer : A

Question. Identify the substances that are oxidised and the substances that are reduced in the following reactions. CuO(s) + H₂(g)→ Cu(s) + H₂O(l)
(a) Cu is oxidised, H₂O is reduced
(b) CuO is oxidised, H₂O is reduced
(c) H₂ is oxidised, CuO is reduced
(d) H₂ is oxidised, H₂O is reduced

Answer : C

Question9. A solution of a substance ‘X’ is used for white washing. Name the substance ‘X’ and write its formula)
(a) Lime stone, CaCO₃
(b) Lime , CaCO₃
(c) Calcium oxide , CaO
(d) Calcium carbonate , CaCO₃

Answer : C

Question. Write the balanced reaction of Calcium oxide with water and state what type of reaction is this
(a) CaO + H₂O→ CaOH + H₂, displacement
(b) CaO + H₂O → Ca(OH)₂, combination
(c) CaO + H₂O→ Ca(OH)₂, decomposition
(d) CaO + H₂O→ CaOH, combination

Answer : B

Question : The reaction in which two compounds exchange their ions to form two new compounds is -
(a) a displacement reaction
(b) a decomposition reaction
(c) an isomerization reaction
(d) a double displacement reaction

Answer :  D

Question : When green coloured ferrous sulphate crystals are heated, the colour of the crystal changes because
(a) it is decomposed to ferric oxide
(b) it loses water of crystallisation
(c) it forms SO₂
(d) it forms SO₃

Answer :  B

Question : A compound used for whitewashing is
(a) Quick lime
(b) Slaked Lime
(c) Blue vitriol
(d) Limestone

Answer :  B

Question. When S0₂ gas is passed through saturated solution of H2S, which of the following reaction occurs? A
(a) SO₂ + 2H₂S → 2H₂0 + 3S
(b) SO₂ + 2H₂S → H₂0 + 3S
(c) SO₂ + H₂S → H₂O + S
(d) SO₂ + H₂O → SO₃ + H₂

Answer : C

Question. Color of magnesium oxide is 
(a) White
(b) Blue
(c) Grey
(d) Pink

Answer : C

Question. A substance x is an oxide of an group 2 element is used in cement industry. On treatment with water it forms solution which turns red litmus to blue. Identify X ? 
(a) Slaked lime
(b) Limestone
(c) Quicklime
(d) Silver sulphide

Answer : C

Question. Which of the following is true for an unbalanced chemical equation? 
(a) Number of atoms is equal on both sides of the equation
(b) Number of atoms is less on the left side of the equation
(c) Number of atoms is more on the right side of the equation
(d) Both (b) and (c).

Answer : D

Question. Which reactant is reduced in given reaction 
CuO + H₂ → Cu + H₂O
(a) Hydrogen
(b) Oxygen
(c) Copper Oxide
(d) none of the above.

Answer : C

Question. Which of the following does not involve a chemical reaction? 
(a) Digestion of food in our body
(b) Process of respiration
(c) Burning of candle wax when heated
(d) Melting of candle wax on heating

Answer : D

Question. The neutralization reaction between an acid and a base is a type of: 
(a) Double displacement reaction
(b) Displacement reaction
(c) Addition reaction
(d) Decomposition reaction

Answer : A

Question. Which of the following statements about the reaction below are incorrect? 
2PbO(s) C(s) ⟶ 2Pb(s) CO2(g)
1. Lead is getting reduced.
2. Carbon dioxide is getting oxidized.
3. Carbon is getting oxidized.
4. Lead oxide is getting reduced.
(a) 1 and 2
(b) 1 and 3
(c) 1, 2 and 3
(d) all of the above

Answer : A

Question. On immersing an iron nail in CuSO₄ solution for a few minutes, you will observe 
(a) No reaction takes place
(b) The color of solution fades away
(c) The surface of iron nails acquire a black coating
(d) The color of solution changes to green

Answer : D

Question. Which of the following is not physical change? 
(a) Boiling of water to give water vapour
(b) Melting of ice to give water
(c) Dissolution of salt in water
(d) Combustion of Liquefied Petroleum Gas (LPG)

Answer : D

Question. The chemical reaction between two substances is characterized by a change in colour from Orange to green. These two substances are most likely to be 
(a) Potassium dichromate solution and Sulphur dioxide
(b) Potassium permanganate solution and Sulphur dioxide
(c) Potassium permanganate solution and lemon juice
(d) Potassium dichromate solution and carbon dioxide

Answer : A

Question. We store silver chloride in a dark coloured bottle because it is 
(a) a white solid
(b) undergoes redoc reaction
(c) to avoid action by sunlight
(d) none of the above

Answer : C

Question. Which substance is used for white washing? 
(a) Quick lime
(b) Washing soda
(c) slaked lime
(d) limestone

Answer : A

Question. Which of the following is formed when lead metal reacts with the solution of copper chloride? 
(a) No reaction takes place
(b) Copper chlorine
(c) Lead chloride
(d) Copper-lead chloride

Answer : C

Question. The respiration process during which glucose undergoes slow combustion by combining with oxygen in the cells of our body to produce energy, is a kind of:
(a) Exothermic process
(b) Endothermic process
(c) Reversible process
(d) Physical process

Answer: A

Question. In a chemical reaction between sulphuric acid and barium chloride solution the white precipitates formed are of:
(a) Hydrochloric acid
(b) Barium sulphate
(c) Chlorine
(d) Sulphur

Answer: B

Question. One of the following processes does not involve a chemical reaction. That is:
(a) Melting of candle wax when heated
(b) Burning of candle wax when heated
(c) Digestion of food in our stomach
(d) Ripening of banana

Answer: A

Question. A chemical reaction does not involve:
(a) Formation of new substances having entirely different properties than that of the reactants
(b) Breaking of old chemical bonds and formation of new chemical bonds
(c) Rearrangement of the atoms of reactants to form new products
(d) Changing of the atoms of on element into those of another element to form new products

Answer: D

Question. The displacement reaction between iron (III) oxide and a metal X is used for welding the rail tracks. Here X is:
(a) Copper granules
(b) Magnesium ribbon
(c) Sodium pellets
(d) Aluminium dust

Answer: D

Question. It is necessary to balance a chemical equation in order to satisfy the law of:
(a) Conservation of motion
(b) Conservation of momentum
(c) Conservation of energy
(d) Conservation of mass

Answer: D

Question. All the methods mentioned below can be used to prevent the food from getting rancid except:
i. Storing the food in the air-tight containers
ii. Storing the food in refrigerator
iii. Keeping the food in clean and covered containers
iv. Always touching the food with clean hands
(a) (i) and (ii)
(b) (i) and (iii)
(c) (i), (iii) and (iv)
(d) (iii) and (iv)

Answer: D

Question. Rusting of iron involves a chemical reaction which is a combination of:
(a) Reduction as well as combination reactions
(b) Oxidation as well as combination reactions
(c) Reduction as well as displacement reactions
(d) Oxidation as well as displacement reactions

Answer: B

Question. You are given the following chemical reaction:
This reaction represents:
(a) Combination reaction as well as double displacement reaction
(b) Redox reaction as well as displacement reaction
(c) Double displacement reaction as well as redox reaction
(d) Decomposition reaction as well as displacement reaction

Answer: B

Question. When ferrous sulphate is heated strongly it undergoes decomposition to form ferric oxide as a main product accompanied by a change in colour from:
(a) Blue to green.
(b) Green to blue.
(c) Green to brown.
(d) Green to yellow.

Answer: C

Question. The chemical reaction between Hydrogen sulphide and iodine to give Hydrogen iodide and sulphur is given below:
The reducing and oxidizing agents involved in this redox reaction are:
(a) Iodine and sulphur respectively
(b) Iodine and hydrogen sulphide respectively
(c) Sulphur and iodine respectively
(d) Hydrogen sulphide and sulphur

Answer: B

Question. Which of the following gases is used in the storage of fat and oil containing foods for a long time?
(a) Carbondioxide gas
(b) Nitrogen gas
(c) Oxygen gas
(d) Neon gas

Answer: B

Question. Following is given a diagram showing an experimental set-up:
The given set-up is used to carry out:
(a) Distillation of water
(b) Purification of water
(c) Electrolysis of water
(d) Hydrolysis

Answer: C

Question. Before burning in air, the magnesium ribbon is cleaned by rubbing with a sand paper to:
(a) Make the ribbon surface shinier
(b) Remove the layer of magnesium oxide from the ribbon surface
(c) Remove the layer of magnesium carbonate from the ribbon surface
(d) Remove the moisture from the ribbon surface

Answer: C

Question : A substance which oxidises itself and reduces other is known as -
(a) oxidising agent
(b) reducing agent
(c) both of these
(d) none of these

Answer :  B

Question : Which of the following gases can be used for storage
(a) Carbon dioxide or Oxygen
(b) Nitrogen or Oxygen
(c) Carbon dioxide or Helium
(d) Helium or Nitrogen

Answer :  D

Question : When carbon dioxide is passed through lime water,
(a) calcium hydroxide is formed
(b) white precipitate of CaO is formed
(c) lime water turns milky
(d) colour of lime water disappears.

Answer :  C

Question : Oxidation is a process which involves
(a) addition of oxygen
(b) addition of hydrogen
(c) removal of oxygen
(d) removal of hydrogen

Answer :  A

Question : In an electrolytic cell where electrolysis is carried, anode has:
(a) Positive change
(b) Negative charge
(c) Connected to negative terminal of the battery
(d) None of these is correct

Answer :  A

Question : To indicate the presence of gaseous reactant or product, we use the symbol
(a) (Product)g or (Reactant)g
(b) (Product)- or (Reactant)-
(c) (Product). or (Reactant).
(d) Both (a) and (b)

Answer :  D

Question : When dilute HCl is added to zinc pieces taken in a test tube
(a) No change takes place
(b) the colour of the solution becomes yellow.
(c) A pungent smelling gas gets liberated.
(d) small bubbles of H2 gas appear on the surface of zinc pieces

Answer :  D

Question : Which of the following is a physical change?
(a) Formation of curd from milk
(b) Ripening of fruits
(c) Getting salt from sea water
(d) Burning of wood

Answer :  C

Question : A dilute ferrous sulphate solution was gradually added to the beaker containing acidified permanganate solution. The light purple colour of the solution fades and finally disap¬pears. Which of the following is the correct explanation for the observation?
(a) KMnO4 is an oxidising agent, it oxidises FeSO4.
(b) FeSO4 acts as an oxidising agent and oxidises KMNO₄.
(c) The colour disappears due to dilution; no reaction is involved.
(d) KMnO4 is an unstable compound and de-composes in presence of FeSO4. to a colourless compound.

Answer :  A

Question : A substance added to food containing fats and oils is called:
(a) Oxidant
(b) Rancid
(c) Coolant
(d) Antioxidant

Answer :  D

Question : Lead nitrate Pb(NO₃)₂ on heating forms Lead oxide (PbO) solid and Nitrogen dioxide gas. What are the color of lead oxide and nitrogen dioxide?
(a) White, Colourless
(b) White, Brown
(c) Yellow, Brown
(d) Yellow, Colourless

Answer :  C

Question : One of the following is an endothermic reaction. This is
(a) Combination of carbon and oxygen to form carbon monoxide
(b) Combination of nitrogen and oxygen to form nitrogen monoxide
(c) Combination of glucose and oxygen to form carbon dioxide and water.
(d) Combination of zinc and hydrochloric acid to form zinc chloride and hydrogen

Answer :  B

Question : Magnesium ribbon is rubbed before burning because it has a coating of
(a) basic magnesium carbonate
(b) basic magnesium oxide
(c) basic magnesium sulphide
(d) basic magnesium chloride

Answer :  A

Question : Ethane (C₂H₆) on complete combustion gave CO₂ and water. It shows that the results are in accordance with the law of conservation of mass. Then, the coefficient of oxygen is equal to
(a) 3
(b) 5/2
(c) 2
(d) 7/2

Answer :  D

Question :  The process of reduction involves
(a) addition of oxygen
(b) addition of hydrogen
(c) removal of oxygen
(d) removal of hydrogen

Answer :  B

Question : Name the products formed when iron filings are heated with dilute hydrochloric acid
(a) Fe (III) chloride and water
(b) Fe (II) chloride and water
(c) Fe (II) chloride and hydrogen gas
(d) Fe (III) chloride and hydrogen gas

Answer :  D

Question : Assertion: Zinc reacts with sulphuric acid to form zinc sulphate and hydrogen gas and it is displacement reaction.
Reason: Zinc reacts with oxygen to form zinc oxide.
(a) Both A and R are true and R is the correct explanation of (a)
(b) Both A and R are true but R is not the correct explanation of (a)
(c) A is true but R is false.
(d) A is false but R is true.
(e) Both A and R are false.

Answer :  B

Question : A reaction of hydrogen with oxygen to form water is a
(a) Endothermic reaction
(b) Exothermic reaction
(c) Decomposition reaction
(d) Reaction not feasible

Answer :  B

Question :  What is observed when a solution of potassium iodide is added to silver nitrate solution?
(a) No reaction takes place
(b) White precipitate of silver iodide is formed
(c) yellow precipitate of Agl is formed
(d) Agl is soluble in water.

Answer :  C

Question : Magnesium ribbon is cleaned before burning. Why?
(a) It absorbs moisture from the atmosphere which interferes with burning.
(b) It’s outer layer form oxides which interfere with burning.
(c) Dust from the atmosphere prevents its burning.
(d) All of the above

Answer :  B

Question : Give the ratio in which hydrogen and oxygen are present in water by volume.
(a) 1:2
(b) 1:1
(c) 2:1
(d) 1:8

Answer :  A

Question : The condition produced by aerial oxidation of fats and oils in foods marked by unpleasant smell and taste is called:
(a) antioxidation
(b) reduction
(c) rancidity
(d) corrosion

Answer :  C

Question : To facilitate the electrolysis of water we add a few drops of acids like sulfuric acid or salts like NaCl. Because:
(a) It acts as a catalyst
(b) It prevents the decomposition of electrodes used.
(c) It increases the electrical conductivity of water.
(d) None

Answer :  C

Question : Silver article turns black when kept in the open for a few days due to formation of
(a) H₂S
(b) AgS
(c) AgSO₄
(d) Ag₂S

Answer : D

Question : Which of the following does not involve a chemical reaction?
(a) Digestion of food in our body
(b) Process of respiration
(c) Burning of candle wax when heated
(d) Melting of candle wax on heating

Answer : D

Question : When Ag is exposed to air it gets a black coating of
(a) AgNO₃
(b) Ag2S
(c) Ag2O
(d) Ag2CO₃

Answer : B

Fill in the Blanks :

Question. The addition of oxygen to a substance is called …………. whereas removal of oxygen is called …………. . 
Answer : oxidation, reduction

Question. A balanced chemical equation has equal masses of various elements in ___________ and ___________ .
Answer : reactants, products

Question. Reaction in which an element displaces another element from its compound is called …………. .
Answer : displacement reaction

Question. Two antioxidants which are usually added to fat and oil containing foods to prevent rancidity, are …………., …………. .
Answer : BHA and BHT

Question…………. is the process in which metals are eaten up gradually by the action of air, moisture or a chemical on their surface.
Answer : Corrosion

Question. is an example of ___________ reaction.
Answer : decomposition

Question. The addition of hydrogen to a substance is called …………. whereas removal of hydrogen is called …………. .
Answer : reduction, oxidation

Question. Precipitation reactions produce insoluble …………. .
Answer : salts

Question. Reactions in which energy is given out are known as …………. .
Answer : exothermic reactions

Question. The colour of FeSO₄ crystal before ___________ heating is and after heating is ___________ .
Answer :  green, reddish brown

Question. SO₂ + 2H₂S → 2H₂O + 3S; SO₂ is ___________ acting as agent.
Answer : oxidising

Question. 2 FeSO₄ → Fe₂O₃ + SO₂ + ………….
Answer : SO₃

Question. Na₂SO₄ + BaCl₂ → …………. + 2NaCl
Answer : BaSO₄

Question. Complete the missing components/variables given as x and y in the following reactions:
(a) Pb (NO₃)₂ (aq) + 2KI (aq) → Pbl₂ (x) + 2KNO₃ (y)
(b) Cu (s) + 2AgNO₃ (aq) → Cu (NO₃)₂ (aq) + x (s)
Answer : (a) x → (s); y → (aq); (b) x → 2Ag

Question. The reaction Cu + xHNO₃ (cone.) → Cu(NO₃)₂ + yNO₂ + zH₂O The values of x, y and z are ___________ , ___________ and ___________ .
Answer : 4, 2 and 2

True Or False :

Question. In H2S + Cl2 → 2HCl + S, Cl2 is oxidising agent and H2S is reducing agent. 
Answer : True

Question. CaO + 2HCl → CaCl2 + H2O is neutralisation reaction. 
Answer : True

Question. Chemical reactions are those processes where new substances with old properties are formed. 
Answer : False

Question. All combustion reactions are oxidation reactions. 
Answer : True

Question. Displacement reaction can be redox reaction also. 
Answer : True

Question : Redox reactions are those where ___ simultaneously.
(a) exothermic - endothermic reactions occur
(b) oxidation - reduction occur
(c) reversible - irreversible reactions occur
(d) composition - decomposition reactions occur

Answer : B

Question : Redox reactions are useful in
(a) bleaching industry
(b) extraction of metals
(c) dying industry
(d) all of these

Answer : B

Question : In a chemical reaction, if one of the product is a gas which burns with a ‘pop’, then the gas is
(a) Cl₂
(b) O₂
(c) H₂
(d) CO₂

Answer : C

Question : The gas which turns lime water milky is
(a) SO
(b) CO
(c) CO₂
(d) H₂S

Answer : C

Question : The gas which has a characteristic pungent smell is
(a) NH₃
(b) Cl₂
(c) SO₂
(d) H₂

Answer : A

Question : The gas which smells like rotten eggs is
(a) CO₂
(b) NO₂
(c) SO₂
(d) H₂S

Answer : D

Question : The formation of gas bubbles in a liquid during a reaction is called
(a) fuzzing
(b) bubbling
(c) deliquidizing
(d) effervescence

Answer : D

Question : CuSO₄ + Fe ® FeSO₄ + Cu. During this reaction change of colour occurs as
(a) blue to pale green
(b) blue to black
(c) white to blue
(d) white to black

Answer : B

Question : Pb(NO₃)² which is colourless, reacts with H₂S to give a precipitate of PbS, whose colour is
(a) brown
(b) white
(c) black
(d) green

Answer : C

Question : In the electrolysis of water, liquid water decomposes into its
(a) two gaseous constituents
(b) one gaseous and one liquid constituent
(c) two liquid constituents
(d) two solid constituents

Answer : A

Question : H₂S + Cl₂ ® 2HCI + S In the above reaction, the gaseous reactants produce
(a) two solid products
(b) one gaseous and one solid product
(c) one liquid and one solid product
(d) one gaseous and one liquid product

Answer : B

Question : Solubility of a solute
(a) increases with temperature
(b) decreases with temperature
(c) remains constant
(d) none of these

Answer : A

Question : 4Fe + 3O₂ ¾¾®2Fe₂O₃ This reaction is
(a) moderate
(b) very fast
(c) very slow
(d) instantaneous

Answer : C

Question : Complete the reaction 2 Mg + 2H O¾¾®?
(a) Mg + 2H₂O
(b) Mg + H₂ + O₂
(c) MgO + H₂
(d) Mg(OH)₂+ H₂

Answer : D

Question : When Mg ribbon is dipped in a test tube containing conc. HCI, products formed are
(a) Mg + H₂ + Cl₂
(b) MgCl₂ + H₂
(c) Mg + Cl₂
(d) Mg+ H₂

Answer : B

Question : Which of the following is the fastest reaction?
(a) aluminium foil + NaOH + heat
(b) aluminium foil + NaOH
(c) aluminium powder + NaOH
(d) all the above

Answer : C

Question : Reaction in which heat energy is released is called
(a) irreversible
(b) reversible
(c) endothermic
(d) exothermic

Answer : D

Question : A catalyst when added to a chemical reaction changes the
(a) colour of the reactants
(b) course of the reaction
(c) speed of the reaction
(d) physical state of the products

Answer : C

Question : During the process of photosynthesis the catalyst is
(a) sunlight
(b) chlorophyll
(c) CO₂
(d) glucose

Answer : B

Question : In our body the catalyst which helps to break down food is
(a) dil HCI
(b) hormones
(c) NaOH
(d) digestive enzymes

Answer : D

Question : Which of the following is a reversible reaction?
(a) CaCO₃ + 2HCI ® CaCl₂ + CO₂+H₂O
(b) 2Mg + O₂® 2MgO
(c) N₂ + 3H₂ ® 2NH₃
(d) Fe + CuSO₄ ® FeSO₄ + Cu

Answer : C

Question : An example of exothermic reaction is
(a) CaO + H₂O ® Ca(OH)²
 (b) CaCO₃ ® CaO + CO₂
(c) 4Fe + 3O₂ ® 2Fe₂O₃
(d) 2Mg + O₂ ® 2MgO

Answer : A

Question : During photosynthesis, CO₂ reacts with H₂O to form glucose. The energy required for the reaction is obtained
(a) by heating
(b) from sunlight
(c) from electric current
(d) from CO₂

Answer : B

Question : In the decomposition of NH₄CI, the products formed are
(a) N₂ + Cl₂
(b) NH₃ + HCI
(c) H₂ + Cl₂
(d) N₂ + HCI

Answer : B

Question : Water breaks into its constituents
(a) by magnetic effect
(b) by light
(c) by heating
(d) by passing electric current

Answer : C

Question : CuSO₄ + Zn → Cu + ZnSO₄ This reaction is an example of a: 

Question : The reactian H₂ + Cl₂ → 2 HCl is a : 
a) Decomposition reaction
b) Combination reaction
c) Double displacement reaction
d) Displacement reaction 
Answer : B

Question : Neutralization reaction is an example of : 
a) Exothermic reaction
b) Endothermic reaction
c) Oxidation reaction
d) None of these
Answer : A

Question : Which of the following statements is/are true? 
a) The total mass of the system remains same in a chemical change.
b) A chemical change is permanent and irreversible.
c) A physical change is temporary and reversible
d) All of these
Answer : D

Question : Which of the following statements is incorrect? 
a) In oxidation, oxygen is added to a substance
b) In reduction, hydrogen is added to a substance
c) Oxidising agent is oxidized
d) Reducing agent is oxidized
Answer :  D