Multiple Choice Questions
Chemical Reactions and Equations
Practice Questions with Answers
Total 135 questions available
Q. 1
Dissolving suger is an example of
A
Physical changeB
None of these.C
Redox ReactionD
Chemical changeClick an option to check your answer
Q. 2
AMg3N2 + bH2O → cMg(OH)2 + dNH3. When the equation is balanced, the coefficients a, b, c, d respectively are -
A
1, 6, 3, 2B
1, 2, 3, 2C
2, 3, 6, 2D
1, 3, 3, 2Click an option to check your answer
Q. 3
Electrolysis of water is a decomposition reaction.
The mole ratio of hydrogen and oxygen gases
liberated during electrolysis of water is ________ .
A
4:1B
2:1C
1:2D
1:1Click an option to check your answer
Q. 4
Write the balanced reaction of Calcium oxide with water and state what type of reaction is this
A
CaO + H2O→ Ca(OH)2, decompositionB
CaO + H2O→ CaOH + H2, displacementC
CaO + H2O→ CaOH, combinationD
CaO + H2O → Ca(OH)2, combinationClick an option to check your answer
Q. 5
The reaction in which two compounds exchange their ions to form two new compounds is -
A
an isomerization reactionB
a double displacement reactionC
a displacement reactionD
a decomposition reactionClick an option to check your answer
Q. 6
The condition produced by aerial oxidation of fats and oils in foods marked by unpleasant smell and taste is called:
A
corrosionB
rancidityC
reductionD
antioxidationClick an option to check your answer
Q. 7
The reaction of H2 gas with oxygen gas to form water is an example of
A
all of these reactionsB
exothermic reactionC
combination reactionD
redox reactionClick an option to check your answer
Q. 8
What occurs in a decomposition reaction?
A
Formation of a single productB
Breakdown of a single reactant into multiple productsC
Combination of multiple reactants into a single productD
No change in reactants or productsClick an option to check your answer
Q. 9
During the process of photosynthesis the catalyst is
A
glucoseB
CO2C
chlorophyllD
sunlightClick an option to check your answer
Q. 10
Which law governs the concept of balanced chemical equations?
A
Law of conservation of energyB
Law of conservation of massC
Avogadro's lawD
Boyle's lawClick an option to check your answer
Q. 11
When does a displacement reaction happen?
A
Two substances combine to form a single substanceB
A single substance decomposes to give multiple substancesC
Loss of hydrogen occursD
An element displaces another from its compoundClick an option to check your answer
Q. 12
The formation of gas bubbles in a liquid during a reaction is called
A
deliquidizingB
fuzzingC
effervescenceD
bubblingClick an option to check your answer
Q. 13
Which of the following does not involve a chemical reaction?
A
Melting of candle wax on heatingB
Digestion of food in our bodyC
Burning of candle wax when heatedD
Process of respirationClick an option to check your answer
Q. 14
A reaction of hydrogen with oxygen to form water is a
A
Exothermic reactionB
Decomposition reactionC
Endothermic reactionD
Reaction not feasibleClick an option to check your answer
Q. 15
Water breaks into its constituents
A
by passing electric currentB
by heatingC
by lightD
by magnetic effectClick an option to check your answer
Q. 16
What is the significance of balancing chemical equations?
A
To obey the law of conservation of massB
To increase reaction ratesC
To ensure reaction reversibilityD
To predict reaction outcomesClick an option to check your answer
Q. 17
CuSO4 + Zn → Cu + ZnSO4 This reaction is an example of a:
A
Displacement reaction.B
Decomposition reaction.C
Combination reaction.D
Double displacement reaction.Click an option to check your answer
Q. 18
What is represented by symbols of elements and formulae of substances in chemistry?
A
Chemical reactionsB
Physical changesC
Atomic structuresD
Molecular bondsClick an option to check your answer
Q. 19
What is oxidation?
A
Gain of oxygen or loss of hydrogenB
Loss of oxygen or gain of hydrogenC
Gain of hydrogen or loss of oxygenD
Loss of hydrogen or gain of oxygenClick an option to check your answer
Q. 20
Name the component of our diet, decomposition of which produces the amino acid.
A
ProteinB
StarchC
CarbohydrateD
FatClick an option to check your answer
Q. 21
What is the primary goal of balancing a chemical equation?
A
To alter the formulae of compoundsB
To change the reactants into productsC
To ensure conservation of massD
To increase the reaction rateClick an option to check your answer
Q. 22
When dilute HCl is added to zinc pieces taken in a test tube
A
A pungent smelling gas gets liberated.B
small bubbles of H2 gas appear on the surface of zinc piecesC
the colour of the solution becomes yellow.D
No change takes placeClick an option to check your answer
Q. 23
Which of the following reactions involves the combination of two elements ?
A
4Na + O2 → 2Na2OB
SO2 + 1/2 O2 → SO3C
NH3 + HCl → NH4ClD
CaO + CO2 → CaCO3Click an option to check your answer
Q. 24
The gas which turns lime water milky is
A
CO2B
H2SC
COD
SOClick an option to check your answer
Q. 25
In a balanced chemical equation, what remains constant?
A
Total number of atomsB
Reactant massC
Product massD
Total number of moleculesClick an option to check your answer
Q. 26
What happens when dilute Sulphuric acid is added to Zn granules? Tick the correct answer.
A
Zinc salt and water are produced)B
Hydrogen gas and Zinc chloride are produced)C
Chlorine gas and Zinc hydroxide are produced)D
No reaction takes place.Click an option to check your answer
Q. 27
Magnesium ribbon is rubbed before burning because it has a coating of
A
basic magnesium sulphideB
basic magnesium carbonateC
basic magnesium chlorideD
basic magnesium oxideClick an option to check your answer
Q. 28
Which of the following reactions is an
endothermic reaction ?
A
Decomposition of calcium carbonate to form quick lime and carbon dioxide.B
Process of respiration.C
Decomposition of vegetable matter into compost.D
Burning of coalClick an option to check your answer
Q. 29
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
Yellow, ColourlessB
White, ColourlessC
White, BrownD
Yellow, BrownClick an option to check your answer
Q. 30
What happens to the number of products in a decomposition reaction?
A
DecreasesB
IncreasesC
Remains the sameD
ReversesClick an option to check your answer
Q. 31
Which of the following reaction is not feasible?
A
Iron + Zinc sulphate solutionB
Copper + Zinc sulphateC
Aluminium + Copper sulphateD
Zinc + Copper sulphate solutionClick an option to check your answer
Q. 32
A dilute ferrous sulphate solution was gradually
added to the beaker containing acidified
potassium permanganate solution. The light
purple colour of the solution fades and finally
disappears. Which of the following is the correct
explanation for the observation?
A
KMnO4 is an unstable compound and decomposes in presence of FeSO4 to a colourless compound.B
The colour disappears due to dilution; no reaction is involved.C
FeSO4 acts as an oxidising agent and oxidises KMnO4D
KMnO4 is an oxidising agent, it oxidises FeSO4Click an option to check your answer
Q. 33
AgNO3(aq) + NaCl(aq) → AgCl(s) + NaNO3(aq). Above reaction is
A
Combination reactionB
Double Displacement reactionC
Precipitation reactionD
A and B bothClick an option to check your answer
Q. 34
What type of reaction is respiration
A
EndothermicB
Combination reactionC
Reduction reactionD
ExothermicClick an option to check your answer
Q. 35
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
7/2B
3C
5/2D
2Click an option to check your answer
Q. 36
Which of the following is true for an unbalanced chemical equation?
A
Number of atoms is less on the left side of the equationB
Number of atoms is equal on both sides of the equationC
Both (b) and (c).D
Number of atoms is more on the right side of the equationClick an option to check your answer
Q. 37
Symbol Δ used while representing some chemical changes stands for -
A
catalystB
pressureC
heatD
lightClick an option to check your answer
Q. 38
Oxidation is a process which involves
A
removal of hydrogenB
addition of oxygenC
addition of hydrogenD
removal of oxygenClick an option to check your answer
Q. 39
Chemical equations balancing is in accordance with:
A
Law of constant proportionsB
Law of combining volumesC
Law of conservation of massD
Both (a) and (c)Click an option to check your answer
Q. 40
In an electrolytic cell where electrolysis is carried, anode has:
A
Connected to negative terminal of the batteryB
None of these is correctC
Positive changeD
Negative chargeClick an option to check your answer
Q. 41
What happens when dilute hydrochloric acid is added to iron filling? Tick the correct answer:
A
Iron salt and water are producedB
Hydrogen gas and iron chloride are produced.C
Chlorine gas and iron hydroxide are producedD
No reaction takes placeClick an option to check your answer
Q. 42
Identify the correct chemical reaction.
A
Hydrogen sulphide gas burns in air to give water and sulphur.B
Potassium metal reacts with water to give potassium hydroxide and water.C
Barium chloride reacts with aluminium sulphate to give aluminium chloride and a precipitate of barium sulphateD
Zinc reacts with silver nitrate to form zinc nitrite and silver.Click an option to check your answer
Q. 43
What happens when dilute Sulphuric acid is added to Zn granules? Tick the correct answer.
A
Zinc salt and water are producedB
No reaction takes place.C
Hydrogen gas and Zinc chloride are producedD
Chlorine gas and Zinc hydroxide are producedClick an option to check your answer
Q. 44
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
H2 is oxidised, CuO is reducedB
CuO is oxidised, H2O is reducedC
H2 is oxidised, H2O is reducedD
Cu is oxidised, H2O is reducedClick an option to check your answer
Q. 45
Which of the following gases can be used
for storage of fresh sample of an oil for a long
time ?
A
HydrogenB
HeliumC
NitrogenD
Carbon dioxideClick an option to check your answer
Q. 46
When electricity is passed through water what kind of reaction takes place?
A
Electrolytic decompositionB
Thermal decompositionC
Displacement reactionD
Photochemical decompositionClick an option to check your answer
Q. 47
When Ag is exposed to air it gets a black coating of
A
Ag2CO3B
Ag2SC
Ag2OD
AgNO3Click an option to check your answer
Q. 48
Burning of the candle is a ________ change.
A
chemicalB
physicalC
none of theseD
both (a) and (b)Click an option to check your answer
Q. 49
The condition produced by aerial oxidation of fats and oils in foods marked by unpleasant smell and taste is called:
A
ReductionB
RancidityC
CorrosionD
AntioxidationClick an option to check your answer
Q. 50
How does the law of conservation of mass apply to chemical reactions?
A
It allows the creation of new substancesB
It prohibits the creation or destruction of matterC
It permits the unequal distribution of mass in reactionsD
It encourages the loss of mass during reactionsClick an option to check your answer
Q. 51
One of the following is an endothermic reaction. This is
A
Combination of nitrogen and oxygen to form nitrogen monoxideB
Combination of glucose and oxygen to form carbon dioxide and water.C
Combination of zinc and hydrochloric acid to form zinc chloride and hydrogenD
Combination of carbon and oxygen to form carbon monoxideClick an option to check your answer
Q. 52
The balancing of chemical equations
is in accordance with:
A
Law of constant proportionsB
Law of conservation of massC
Both b and cD
Law of combining volumesClick an option to check your answer
Q. 53
The neutralization reaction between an acid and a base is a type of:
A
Addition reactionB
Decomposition reactionC
Double displacement reactionD
Displacement reactionClick an option to check your answer
Q. 54
What characterizes a combination reaction?
A
Formation of a new single substanceB
Loss of hydrogenC
Decomposition of a single substanceD
Formation of multiple substancClick an option to check your answer
Q. 55
When ferrous hydroxide reacts with hydrochloric acid, ….. and H2O are produced
A
FeCl2B
FeCl3C
FeClD
FeCl4Click an option to check your answer
Q. 56
When green coloured ferrous sulphate crystals are heated, the colour of the crystal changes because
A
it forms SO3B
it is decomposed to ferric oxideC
it loses water of crystallisationD
it forms SO2Click an option to check your answer
Q. 57
Heating of ferrous sulphate is a type of :
A
Decomposition reactionB
Combination ReactionC
Displacement reactionD
All of the aboveClick an option to check your answer
Q. 58
What type of reaction involves the use of electrical energy for decomposition?
A
Thermal decompositionB
Electrolytic decompositionC
Photochemical decompositionD
Chemical decompositionClick an option to check your answer
Q. 59
What occurs in a decomposition reaction?
A
Formation of a single substanceB
Formation of multiple substancesC
Decomposition of multiple substancesD
Loss of oxygenClick an option to check your answer
Q. 60
In a chemical reaction, if one of the product is a gas which burns with a ‘pop’, then the gas is
A
CO2B
Cl2C
O2D
H2Click an option to check your answer
Q. 61
In photolysis, what form of energy is employed for decomposition?
A
Heat energyB
Electrical energyC
Sound energyD
Light energyClick an option to check your answer
Q. 62
What type of reaction is respiration
A
EndothermicB
Combination reactionC
Reduction reactionD
ExothermicClick an option to check your answer
Q. 63
Which of the following is the fastest reaction?
A
all the aboveB
aluminium powder + NaOHC
aluminium foil + NaOHD
aluminium foil + NaOH + heatClick an option to check your answer
Q. 64
Give the ratio in which hydrogen and oxygen are present in water by volume.
A
1:2B
1:1C
2:1D
1:8Click an option to check your answer
Q. 65
What is the primary characteristic of a decomposition reaction?
A
Breakdown of reactants into simpler substancesB
Formation of a single productC
Combination of multiple reactantsD
Equal numbers of reactants and productsClick an option to check your answer
Q. 66
Color of magnesium oxide is
A
LimestoneB
QuicklimeC
Slaked limeD
Silver sulphideClick an option to check your answer
Q. 67
Which metal is displaced when lead is put in the
solution of copper chloride ?
A
CopperB
All of theseC
LeadD
ChlorineClick an option to check your answer
Q. 68
How does the concept of balanced chemical equations relate to the law of conservation of mass?
A
It allows for the violation of the law of conservation of massB
It contradicts the law of conservation of massC
It has no relation to the law of conservation of massD
It demonstrates the validity of the law of conservation of massClick an option to check your answer
Q. 69
What ensures equilibrium in chemical equations?
A
Reactant concentrationB
Product concentrationC
Balancing of atomsD
TemperatureClick an option to check your answer
Q. 70
On immersing an iron nail in CuSO₄ solution for a few minutes, you will observe
A
The color of solution fades awayB
The color of solution changes to greenC
The surface of iron nails acquire a black coatingD
No reaction takes placeClick an option to check your answer
Q. 71
In the electrolysis of water, liquid water decomposes into its
A
two solid constituentsB
two gaseous constituentsC
one gaseous and one liquid constituentD
two liquid constituentsClick an option to check your answer
Q. 72
Which of the following is true for an unbalanced chemical equation?
A
The number of atoms is more on the right side of the equationB
The number of atoms is less on the left side of the equationC
The number of atoms is equal on both sides of the equationD
Both (a) and (b)Click an option to check your answer
Q. 73
What are the new substances produced in a chemical reaction referred to as?
A
MoleculesB
ElementsC
ReactantsD
ProductsClick an option to check your answer
Q. 74
In a context of redox reactions, the removal of hydrogen from a substance is known as
A
DehydrogenationB
ReductionC
DehydrationD
OxidationClick an option to check your answer
Q. 75
Which reaction uses electricity to decompose substances?
A
Thermal decompositionB
Photochemical decompositionC
Chemical decompositionD
Electrolytic decompositionClick an option to check your answer
Q. 76
What remains constant in chemical reactions?
A
TemperatureB
Reactant concentrationC
Product concentrationD
Total number of atomsClick an option to check your answer
Q. 77
What is observed when a solution of potassium iodide is added to silver nitrate solution?
A
White precipitate of silver iodide is formedB
Agl is soluble in water.C
No reaction takes placeD
yellow precipitate of Agl is formedClick an option to check your answer
Q. 78
What does a balanced chemical equation indicate?
A
A reversible reactionB
A spontaneous reactionC
A quantitative reactionD
A complete reactionClick an option to check your answer
Q. 79
Which form of energy is utilized in thermal decomposition reactions?
A
Light energyB
Electrical energyC
Heat energyD
Chemical energyClick an option to check your answer
Q. 80
A student added dilute HCl to a test tube containing zinc granules and made following observations :
A
a gas evolved which burnt with a pop soundB
the solution remained colourlessC
the solution becomes green in colourD
the zinc surface became dull and blackClick an option to check your answer
Q. 81
When S02 gas is passed through saturated solution of H2S, which of the following reaction occurs? A
A
SO2 + H2S → H2O + SB
SO2 + H2O → SO3 + H2C
SO2 + 2H2S → H20 + 3SD
SO2 + 2H2S → 2H20 + 3SClick an option to check your answer
Q. 82
What is the name of the process where fatty foods
become rancid?
A
CorrosionB
HydrogenationC
OxidationD
ReductionClick an option to check your answer
Q. 83
When Mg ribbon is dipped in a test tube containing conc. HCI, products formed are
A
Mg+ H2B
Mg + H2 + Cl2C
Mg + Cl2D
MgCl2 + H2Click an option to check your answer
Q. 84
Magnesium ribbon is cleaned before burning. Why?
A
It absorbs moisture from the atmosphere which interferes with burning.B
All of the aboveC
It’s outer layer form oxides which interfere with burning.D
Dust from the atmosphere prevents its burning.Click an option to check your answer
Q. 85
In a chemical equation, what are the substances that undergo a reaction called?
A
ElementsB
CompoundsC
ReactantsD
ProductsClick an option to check your answer
Q. 86
Which of the following does not involve a chemical reaction?
A
Process of respirationB
Digestion of food in our bodyC
Melting of candle wax on heatingD
Burning of candle wax when heatedClick an option to check your answer
Q. 87
Reaction in which heat energy is released is called
A
reversibleB
endothermicC
exothermicD
irreversibleClick an option to check your answer
Q. 88
What ensures a balanced chemical equation?
A
Equal reactant and product volumesB
Equal reactant and product massesC
Equal number of atoms of different elementsD
Equal number of molecules in reactants and productsClick an option to check your answer
Q. 89
Which of the following is not physical change?
A
Combustion of Liquefied Petroleum Gas (LPG)B
Dissolution of salt in waterC
Melting of ice to give waterD
Boiling of water to give water vapourClick an option to check your answer
Q. 90
Which principle states that matter cannot be created or destroyed in a chemical reaction?
A
Law of conservation of energyB
Law of conservation of massC
Law of definite proportionsD
Law of multiple proportionsClick an option to check your answer
Q. 91
What does the symbol":"represent in a chemical
reaction ?
A
Precipitate formedB
Gas releasedC
Solid stateD
Direction of reactionClick an option to check your answer
Q. 92
The balancing of chemical equations is in accordance with:
A
Law of constant proportionsB
Law of conservation of massC
Both b and cD
Law of combining volumesClick an option to check your answer
Q. 93
A solution of a substance ‘X’ is used for white washing. Name the substance ‘X’ and write its formula)
A
Calcium oxide , CaOB
Lime stone, CaCO3C
Calcium carbonate , CaCO3D
Lime , CaCO3Click an option to check your answer
Q. 94
Solubility of a solute
A
remains constantB
none of theseC
increases with temperatureD
decreases with temperatureClick an option to check your answer
Q. 95
Which law should be kept in mind while we
balance chemical equations?
A
Conservation of frequencyB
Conservation of momentumC
Conservation of energyD
Conservation of massClick an option to check your answer
Q. 96
Which of the following statements is/are correct ?
A
A chemical equation tells us about the atoms or molecules of the reactants and products involved in a reaction.B
A chemical equation informs us about the symbols and formulae of the substances involved in a reaction.C
A chemical equation tells us about the substances involved in a reaction.D
All the aboveClick an option to check your answer
Q. 97
H2S + Cl2 ® 2HCI + S In the above reaction, the gaseous reactants produce
A
one gaseous and one solid productB
one liquid and one solid productC
one gaseous and one liquid productD
two solid productsClick an option to check your answer
Q. 98
Which one of the following processes involves a
chemical reaction?
A
Storing of oxygen gas under pressure in a gas cylinderB
Heating copper wire in presence of air at high temperatureC
Liquification of airD
Keeping petrol in a china dish in the openClick an option to check your answer
Q. 99
In our body the catalyst which helps to break down food is
A
hormonesB
dil HCIC
NaOHD
digestive enzymesClick an option to check your answer
Q. 100
What is reduction?
A
Gain of oxygen or loss of hydrogenB
Loss of oxygen or gain of hydrogenC
Gain of hydrogen or loss of oxygenD
Loss of hydrogen or gain of oxygenClick an option to check your answer
Q. 101
Which of the folllowing is an example of simple
displacement?
A
the reaction of a metal with an acidB
The reaction of two salt solutions to form a precipitateC
the burning of methaneD
the electrolysis of waterClick an option to check your answer
Q. 102
Fill in the blank in the chemical equation : ……. + 4HNO3 → Cu(NO3)2 + 2NO2 + 2H2O
A
CuOB
CuC
2CuOD
2CuClick an option to check your answer
Q. 103
In the balanced equation Na2CO3 + xHCl → 2NaCl + CO2 + H2O. The value of x is
A
2Al + 6H2O → 2Al(OH)3 + 3H2B
4NH3 + 5O2 → 4NO + 6H2OC
2C4H10 + 12O2 → 8CO2 + 10H2OD
2NaHCO3 → Na2CO3 + H2O + CO2Click an option to check your answer
Q. 104
The reaction which decomposes after the supply
of heat is called
A
Displacement reactionB
Redox reactionC
Thermal decompositionD
Combination reactionClick an option to check your answer
Q. 105
What does an unbalanced chemical equation lack?
A
ReactantsB
ProductsC
Equal numbers of atomsD
Molecular bondsClick an option to check your answer
Q. 106
In a double displacement reaction such as the
reaction between sodium sulphate solution and
barium chloride solution:
(i) exchange of atoms takes place.v (ii) exchange of ions takes place.v (iii) a precipitate is produced.
(iv) an insoluble salt is produced.
The correct option is :
(i) exchange of atoms takes place.v (ii) exchange of ions takes place.v (iii) a precipitate is produced.
(iv) an insoluble salt is produced.
The correct option is :
A
only (ii)B
(ii), (iii) and (iv)C
(ii) and (iv)D
(i) and (iii)Click an option to check your answer
Q. 107
In balancing a chemical equation, what remains constant?
A
Total massB
Reactant concentrationC
Product compositionD
Total number of atomsClick an option to check your answer
Q. 108
In which of the following, the identity of initial
substance remains unchanged?
A
Digestion of foodB
Formation of crystals by process of crystallisationC
Fermentation of grapesD
Curdling of milkClick an option to check your answer
Q. 109
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 carbon dioxideB
Potassium permanganate solution and lemon juiceC
Potassium permanganate solution and Sulphur dioxideD
Potassium dichromate solution and Sulphur dioxideClick an option to check your answer
Q. 110
Pb(NO3)2 which is colourless, reacts with H2S to give a precipitate of PbS, whose colour is
A
whiteB
greenC
brownD
blackClick an option to check your answer
Q. 111
Which of the following is not a displacement reaction?
A
Calcium hydroxide + Carbon dioxide → Calcium carbonate + WaterB
Barium chloride + Potassium sulphate → Barium sulphate + Potassium chlorideC
Aluminium + Copper chloride → Aluminium chloride + CopperD
Potassium bromide (aq) + Barium iodide(aq) → Potassium iodide(aq) + Barium bromide(s)Click an option to check your answer
Q. 112
What does the law of conservation of mass imply about chemical reactions?
A
Mass is always conserved in chemical reactionsB
Mass can be created during reactionsC
Mass can be destroyed during reactionsD
Mass is only conserved in certain reactionsClick an option to check your answer
Q. 113
Which one of the following precipitates are
formed when the carbon dioxide gas is passed
through lime water?
A
Ca(OH)4B
Ca(OH)2C
CaCO₂D
CaCO3Click an option to check your answer
Q. 114
A compound used for whitewashing is
A
Quick limeB
Blue vitriolC
LimestoneD
Slaked LimeClick an option to check your answer
Q. 115
Silver article turns black when kept in the open for a few days due to formation of
A
Ag2SB
H2SC
AgSO4D
AgSClick an option to check your answer
Q. 116
How are reactants and products represented in a chemical equation?
A
By symbols of elementsB
By molecular weightsC
By atomic numbersD
By structural formulasClick an option to check your answer
Q. 117
Which of the following reaction will evolve hydrogen gas with a pop sound?
A
Concentrated nitric acid is reacted with sulphur.B
A small piece of zinc is added to dilute hydrochloric acidC
Ammonia is passed over heated copper (II) oxide.D
Lead Nitrate is heated strongly in a test tube.Click an option to check your answer
Q. 118
The process of reduction involves
A
removal of hydrogenB
removal of oxygenC
addition of oxygenD
addition of hydrogenClick an option to check your answer
Q. 119
Which of the following is not conveyed by a balanced chemical equation?
A
If a particular reaction is practically feasible or not.B
Symbols and formulae of all the reactants.C
Number of atoms and molecules of the products formed.D
The physical state of reactants and products.Click an option to check your answer
Q. 120
In the decomposition of NH4CI, the products formed are
A
NH3 + HCIB
H2 + Cl2C
N2 + HCID
N2 + Cl2Click an option to check your answer
Q. 121
Redox reactions are useful in
A
bleaching industryB
extraction of metalsC
dying industryD
all of theseClick an option to check your answer
Q. 122
Zn + HCl → ZnCl₂ + _________ .
A
ZnB
H₂C
None of theseD
Cl₂Click an option to check your answer
Q. 123
In the equation, a Al + bH2SO4 → c Al2(SO4)3 + dH2 a, b, c, d are respectively -
A
2, 3, 1, 3B
2, 3, 2, 3C
2, 3, 1, 1D
2, 2, 3, 3Click an option to check your answer
Q. 124
Rancidity can be prevented by:
A
storing food away from lightB
keeping food in refrigeratorC
adding antioxidantsD
all of the aboveClick an option to check your answer
Q. 125
A substance added to food containing fats and oils is called:
A
RancidB
OxidantC
AntioxidantD
CoolantClick an option to check your answer
Q. 126
A catalyst when added to a chemical reaction changes the
A
physical state of the productsB
speed of the reactionC
A catalyst when added to a chemical reaction changes theD
colour of the reactantsClick an option to check your answer
Q. 127
Which type of reaction is the opposite of a combination reaction?
A
Thermal decompositionB
Electrolytic decompositionC
Decomposition reactionD
PhotolysisClick an option to check your answer
Q. 128
Which of the following is a physical change?
A
Getting salt from sea waterB
Burning of woodC
Ripening of fruitsD
Formation of curd from milkClick an option to check your answer
Q. 129
A solution of a substance ‘X’ is used for white washing. Name the substance ‘X’ and write its formula)
A
Calcium oxide , CaOB
Calcium carbonate , CaCO3C
Lime , CaCO3D
Lime stone, CaCO3Click an option to check your answer
Q. 130
The blue flame in the below image represents the burning of which metal?
A
All metal burn to give a blue flameB
SodiumC
CopperD
IronClick an option to check your answer
Q. 131
The oxidation reaction which produces heat and
light is called:
A
PhotochemicalB
EndothermicC
ExothermicD
CombustionClick an option to check your answer
Q. 132
Assertion: Zinc reacts with sulphuric acid to form zinc sulphate and hydrogen gas and it is displacement reaction.
A
Both A and R are true but R is not the correct explanation of (a)B
A is false but R is true.C
Both A and R are true and R is the correct explanation of (a)D
A is true but R is false.Click an option to check your answer
Q. 133
Name the products formed when iron filings are heated with dilute hydrochloric acid
A
Fe (II) chloride and waterB
Fe (III) chloride and waterC
Fe (III) chloride and hydrogen gasD
Fe (II) chloride and hydrogen gasClick an option to check your answer
Q. 134
What is the primary requirement for a chemical equation to be balanced?
A
Equal product concentrationsB
Equal reactant concentrationsC
Equal product massesD
Equal numbers of atoms on both sidesClick an option to check your answer
Q. 135
To facilitate the electrolysis of water we add a few drops of acids like sulfuric acid or salts like NaCl. Because:
A
It prevents the decomposition of electrodes used.B
It increases the electrical conductivity of water.C
NoneD
It acts as a catalystClick an option to check your answer
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