Which of the following observations help us to determine whether a chemical reaction has taken place?. 

(a) Change in state

(b) Change in colour

(c) Evolution of gas

(d) all of these

Why should a magnesium ribbon be cleaned before burning in air?

(a) because it can’t be burn without cleaning.

(b) because it has a magnesium oxide layer on it which prevents it from burning in air.

(c) we should not clean ribbon before burning in air

(d) none of these

Calcium oxide reacts vigorously with water to produce: –

(a) Calcium hydride & heat

(b) Calcium hydroxide & large amount of heat

(c) Slaked lime (calcium hydroxide) & large amount of water

(d) options (b) & (c) both

Hint : CaO + H2O→Ca(OH)2 + heat

Substance which used for Whitewashing walls: –

(a) Calcium oxide

(b) Magnesium

(c) Calcium

(d)  all of these

Calcium hydroxide reacts with carbon dioxide to form: –

(a) Calcium carbide & water

(b) Calcium hydrogen carbonate

(c) Calcium carbonate & water

(d) none of these

Hint : Ca(OH)2 +CO2 ———-à CaCO3 + H2O

Chemical formula of marble: –

(a) Calcium hydroxide

(b) Calcium carbonate

(c) Calcium bicarbonate

(d) Calcium oxide

Hint : CaCO3

Such a reaction in which a single product is formed from two or more reactants is known as: –

(a) Oxidation

(b) Corrosion

(c) Double displacement reaction

(d) Combination reaction

Burning of coal is an example of: –

(a) Endothermic reaction

(b) Exothermic reaction (heat generate)

(c) decomposition reaction

(d) options (b) & (a) both

Hint : C + O₂à CO₂ + energy(heat)

Formation of water from hydrogen and oxygen is an example of: –

(a) Decomposition reaction

(b) Combination reaction

(c) Displacement reaction

(d) Reduction

Hint : 2H2+O2 –à 2H2O

Burning of natural gas is an example of: –

(a) Combination reaction

(b) Endothermic reaction

(c) Exothermic reaction

(d) Displacement reaction

Respiration is an –

(a) Endothermic process

(b) Exothermic process

(c) Reversible process

(d) none of these

The reaction in which a single reactant is broken down into two or more than two products are known as: –

(a) Combination reaction

(b) Decomposition reaction

(c) Displacement reaction

(d) Oxidation reaction

Hint :  Aerobic respiration takes place in the mitochondria and requires oxygen and glucose, and produces carbon dioxide, water, and energy. The chemical equation is C6H12O6 + 6O2 → 6CO2 + 6H2O (glucose + oxygen -> carbon dioxide + water).

Decomposition of ferrous Sulphate(FeSo₄(s)) gives: –

(a) Ferrous oxides + Sulphur dioxide only + Sulphur trioxide only

(b) Ferric oxide + Sulphur dioxide only

(c) Ferrous oxide + Sulphur trioxide only

(d) Ferric oxide + Sulphur dioxide + Sulphur trioxide

Hint : FeSo₄(s)– heat—àFe₂O₃ + SO₂ + SO₃

Decomposition of calcium carbonate gives: –

(a) Calcium oxide + Carbon dioxide

(b) Calcium bicarbonate + water

(c) Calcium + Carbon + Oxygen

(d) none of these

Hint : CaCo₃(s)———-à CaO(s) + CO₂(g)

Chemical formula of quick lime is: –

(a) CuO(s)

(b) CaCO₃(s)

(c) Li₂O(s)

(d) CaO(s)

Hint : Calcium oxide

Chemical formula of limestone:-

(a) CaCO₃(s)

(b) CuO(s)

(c) CuCO₃(s)

(d) CaO(s)

Hint : Calcium carbonate

When lead nitrate powder is heated emission of brown fume is observed, this brown fume is: –

(a) Nitrogen dioxide

(b) Iron oxide

(c) Lead oxide

(d) Nitrogen oxide

HInt : 2Pb(NO3)2(s) → 2PbO(s)      +      4NO2(g)       +        O2(g)

           (Lead nitrate)     (Lead oxide)     (Nitrogen dioxide)      (Oxygen)

The brown coloured fumes are of nitrogen dioxide.

Reaction of iron with copper sulphate solution is an example of: –

(a) Combination reaction

(b) Decomposition reaction

(c) Displacement reaction

(d) Corrosion

Hint : Electrochemical series

Fe+CuSO4→FeSO4+Cu

Mark the incorrect statement: –

(a) Zn  can displace Cu from it’s compound

(b) Pb can displace Cu from it’s compound

(c) Zn can displace Pb from it’s compound

(d) Cu can displace Pb from its compound

Reaction between sodium sulphate solution and barium chloride solution is an example of: –

(a) Displacement reaction

(b) Double displacement reaction

(c) Precipitation reaction

(d) options (b) & (c) both

Hint : Na2SO4(aq) + BaCl2(aq) → (insoluble)BaSO4(s)↓ + 2NaCl(aq)

which of the following is or are example of the corrosion

(a) black coating on silver

(b) green coating on copper

(c) rusting of iron

(d) all of the above

Rancidity of the fat containing food materials are due:

(a) antioxidants

(b) oxidation

(c) reduction

(d) none of the above

what is the method of prevention of corrosion

(a) corrosion

(b) oxidation

(c) galvanization

(d) none of the above

what is the method of prevention of rancidity of food materials:

(a) packaging of food and the bags are fill with the nitrogen gas

(b) uses of antioxidants retards the oxidation of oils or fat present in food

(c) storing the food materials in airtight containers

(d) all of the above

Fe₂O₃ + 2Al  ——à Al₂O₃ + 2Fe

(a) Combination Reaction

(b) Double displacement reaction

(c) Decomposition reaction

(d) Displacement Reaction

What happen when dilute hydrochloric acid is added to iron filling?

(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.

Hint : 2HCl + Fe → FeCl2 + H2

when dilute HCl is added to Fe Then Ferrous chloride (FeCl2) and hydrogen gas (H2) will be formed.

What do you mean by the Exothermic reactions

(a) Reactions in which heat is absorbed along with the formation of products

(b) Chlorine gas and iron hydroxide are produced in these reactions

(c) Reactions in which heat is released along with the formation of products

(d) None of the above

which of the following statement is true about a chemical reaction

ZnO + C ———à Zn + CO

(a) Carbon is oxidized

(b) ZnO is reduced

(c) Both a and b

(d) None of the above

when we heat lead nitrate it produces brown fumes name the gas which is responsible for this phenomenon?

(a) Nitrogen dioxide gas

(b) Sulphur dioxide

(c) carbon dioxide

(d) Nitrogen oxide

The decomposition reactions require energy in the form of

(a) Heat

(b) Light

(c) Electricity

(d) All of the above

Which of the following compound is used in black and white photography:

(a) AgCl(s)

(b) AgBr(s)

(c) AgCu(s)

(d) None of these

____________ is formed after 2-3 days of white washing and gives a shiny finish to the wall?

(a) Calcium carbonate

(b) Calcium hydroxide

(c) Both

(d) None of the above

Which of the following is not a physical change?

(a) boiling of water to give water vapor

(b) Melting of ice to give water

(c) dissolution of salt in water

(d) combustion of liquefied petroleum Gas(LPG)

Electrolysis of water is a decomposition reaction. The mole ratio of hydrogen and oxygen gas liberated during electrolysis of water is

(a) 1:1

(b) 2:1

(c) 3:1

(d) 1:2

Which of the following gases can be used for storage of fresh sample of an oil for a long time?

(a) Carbon dioxide or oxygen

(b) Nitrogen

(c) Carbon dioxide or helium

(d) Helium or nitrogen

Which metal can displace copper from copper sulphate solution

(a) Silver

(b) Iron

(c) Mercury

(d) Gold

Solid substances are produced, after chemical reaction is called?

(a) Crystals

(b) Filtrate

(c) Precipitate

(d) All

What is catalyst?

(a) Alter the rate of chemical Reactions

(b) It consumed in reaction and speed up the reaction

(c) it consumed in reaction and slow down the speed of reactions

(d) It doesn’t affect the rate of reactions

Which of the following method is used to protect iron items from rusting?

(1) Galvanisation

(2) Painting

(3) Oiling and greasing

(a) (1) and (3)

(b) (2) and (3)

(c) (3) only

(d) (1) (2) and (3)

What will happen when we react silver metal with dilute hydrochloric acid

(a) The rate of reaction is very fast

(b) The rate of reaction is very slow

(c) silver metal cannot react with dilute hydrochloric acid

(d) This reaction will be exothermic reaction

Why do we store silver chloride in dark coloured bottles?

(1) It is very sensitive to light

(2) It decomposed in the presence of light

(3) It evaporate in the presence of light.

(a) 1 and 3

(b) 1,2 and 3

(c) 1 only

(d) 1 only

Hint :  2AgCl→2Ag + Cl₂

Which of following is not a chemical change.

(a) Burning of a natural gas

(b) Melting of wax

(c) Decomposition of vegetables matter into compost

(d) Respiration

Which of the following is true about following reaction:

“Burning of a magnesium ribbon in Air”

(a) Combination reaction

(b) It gives white powder

(c) Exothermic reaction

(d) All of the above

What is a rancidity?

(a) A process in which fat and oil are oxidized

(b) A process in which fat and oils are reduced

(c) Anti-oxidant process

(d) All of the above

which gas is release when Zinc granules reacts with hydrochloric acid?

(a) Oxygen gas

(b) Nitrogen Gas

(c) Hydrogen Gas

(d) None of the above

Hint : Zn + 2HCl → H₂ + ZnCl₂

Which of the following is not exothermic reactions?

(a) Burning of natural gas

(b) Respiration

(c) Decomposition of vegetables matter into compost

(d) All are exothermic reactions

When calcium oxide reacts with water to produced slaked lime, which of the following statement is true about above reaction:

(a) Its exothermic reactions

(b) combination reaction

(c) both

(d) None of the above

Hint : Ca (s) + 2H2O (l) => Ca(OH) ₂ (aq) + H2 (g)

White silver chloride turns grey in sunlight. Which statement is true about the above reaction?

(a) We got chlorine gas

(b) We got silver metal

(c) Decomposition reaction

(d) All of the above

Which of the following is a displacement reaction?

(a) Iron nails dipped in copper sulphate solution

(b) mixture of sodium sulphate solution and barium chloride solution

(c) Silver bromide turn grey in sunlight

(d) All of the above

Magnesium ribbon burn with which colour of flame?

(a) Yellow Flame

(b) Green Flame

(c) Dazzling white flame

(d) Black Flame

Which of the following pair of reactions is not opposite to each other

(a) Endothermic reaction – Exothermic reaction

(b) Combination reaction – Decomposition reaction

(c) Displacement reaction – Double displacement reaction

(d) Reduction – Oxidation

Which of the following is an example of exothermic reaction?

(a) Burning of natural gas

(b) Dissolution of glucose in water

(c) Electrolysis of water

(d)  Decomposition of hydrogen peroxide

find the coefficients

XH2 + O2 ——à YH2O

(a) 2,3

(b) 2,2

(c) 2,4

(d) 2,1

The carbon dioxide gas is produced during ________________

(a) Incomplete respiration.

(b)Incomplete combustion

(c) complete combustion and respiration

(d) incomplete combustion and respiration

Hint : Incomplete – carbon Mono-oxide

During double displacement reactions

(a) Exchange of gases take place 

(b) Colour change may occurs

(c) Precipitates are formed

(d) All of the above

Which of the following statement is not true about prevention of rancidity?

(a) Refrigeration

(b) Keeping in the sunlight

(c) using anti-oxidants

(d) Creation of vacuum

Why Aluminium articles do not need painting and polishing?

(a) Aluminium article does not participate in corrosion.

(b) Aluminium article does not react with any gas

(c) Aluminium metal react with oxygen form inert layer of aluminium oxide

(d) none of these

Reaction in which energy is absorbed are known as:

(a) Endothermic reaction

(b) Exothermic reaction

(c) Both

(d) None of the above

Decomposition reaction as opposite to which of the following reaction

(a) Displacement reaction

(b) Double displacement reaction

(c) Combination reaction

(d) All of the above

What is redox reaction

(a) Oxidation

(b) Reduction

(c) Both

(d) None

When aqueous solution of sodium sulphate and barium chloride are

mixed together, it becomes

(a) turns red

(b) forms a white precipitate

(c) forms yellow precipitate

(d) becomes colourless

Hint : Na2(SO4) + Ba Cl2 ——— 2NaCl +BaSO4(white precipitate)

A student took solid quick lime in a china dish and added a small amount of water to it. He would hear

(a) pop sound

(b) a crackling sound

(c) hissing sound

(d) no sound at all

The colour of ferrous sulphate crystals is

(a) Yellow

(b) Light Green

(c) Yellow

(d) White

A balanced chemical equation is in accordance with-

(a) Avogadro’s law

(b) law of multiple proportion

(c) law of conservation of mass

(d) law of gaseous volumes

White silver chloride in sunlight turns to-

(a) grey

(b) yellow

(c) remain white

(d) red

ASSERTION: nitrogen is flushed in Potato chips packet to preserve rancid of potato.

REASON: Nitrogen prevents contact of chips to air and thus prevents oxidation.

(a) A is
correct but R is wrong.

(b) A is
wrong but R is correct.

(c) Both A
and R are False.

(d) Both A
and R are true and R is the correct explanation of A.

(e) Both A
and R are true but R is not the correct explanation of A.

ASSERTION: The chemical reaction during which hydrogen gas is lost is called reduction reaction

REASON: Reducing agent remove hydrogen

(a) A is correct but R is wrong.

(b) A is wrong but R is correct.

(c) Both A and R are False.

(d) Both A and R are true and R is the correct explanation of A.

(e) Both A and R are true but R is not the correct explanation of A.

ASSERTION: Photosynthesis is considered as an endothermic reaction 

REASON : Energy gets released in the process photosynthesis

(a) A is correct but R is wrong.

(b) A is wrong but R is correct.

(c) Both A and R are False.

(d) Both A and R are true and R is the correct explanation of A.

(e) Both A and R are true but R is not the correct explanation of A.

ASSERTION: Quicklime reacts vigorously with water releasing a large amount of heat.

REASON: The above chemical reaction is and exothermic reaction

(a) A is correct but R is wrong.

(b) A is wrong but R is correct.

(c) Both A and R are False.

(d) Both A and R are true and R is the correct explanation of A.

(e) Both A and R are true but R is not the correct explanation of A.

ASSERTION: White silver chloride turns grey in sunlight

REASON: Decomposition of silver chloride in presence of sunlight takes place to form silver metal and chlorine gas.

(a) A is correct but R is wrong.

(b) A is wrong but R is correct.

(c) Both A and R are False.

(d) Both A and R are true and R is the correct explanation of A.

(e) Both A and R are true but R is not the correct explanation of A.