ICSE Class 10 Chemistry Question Paper Solution 2020

Students can find the ICSE Class 10 Chemistry Question Paper Solution 2020 on this page. Solving the questions of the 2020 Chemistry paper and then going through the answers will help students evaluate their exam preparation. They get to know the topics and areas where they have to put extra effort. Solving the 2020 Chemistry paper will also provide a good revision to students.

Download ICSE Class 10 Chemistry Question Papers Solutions 2020 PDF

The ICSE Class 10 Chemistry 2020 exam was conducted on 16th March 2020. The exam started at 11 am, and students were allotted 2 hours to finish the paper. They can download the ICSE Class 10 Chemistry Question Paper Solution 2020 PDF from the link below.

Students can have a look at the ICSE Class 10 Chemistry Question Paper Solution 2020 below. They can also access the year wise ICSE Class 10 Chemistry Solved Previous Year Question Papers for more practice.

Difficult Topics of ICSE Class 10 Chemistry 2020 Question Paper

Below we have listed down the topics which students found difficult while attempting the ICSE 2020 Chemistry Question Paper.

• Properties of Ionic and covalent compounds
• Writing balanced chemical equations for the given chemical reactions
• Identification of gases and compounds
• Drawing structural formulae of organic compound
• Drawing of isomers
• Methods of preparation of salts
• Identifying the salts from the given observations
• Electron dot diagram
• Oxidation / Reduction reaction applied to electrolysis
• Reactions and observation at cathode and anode
• Problems based on Mole concept
• Observation based questions on practical chemistry
• Distinguishing between pairs of compound by using a particular reagent
• Reaction of ammonia with excess chlorine and vice versa
• Oxidation and reduction in terms of loss and gain of electrons
• IUPAC names, common names and numbering of the carbon atoms in the chain
• Usage of the sign < and >
• Electro-negativity and Electron affinity
• Reasoning type questions

ICSE Class 10 Chemistry Question Paper 2020 With Solutions

Question 1:

(a) Choose the correct answer from the options given below:

(i) The element with highest ionization potential, is:

A. Hydrogen

B. Caesium

C. Radon

D. Helium

(ii) The inert electrode used in the electrolysis of acidified water, is:

A. Nickel

B. Platinum

C. Copper

D. Silver

(iii) A compound with low boiling point, is:

A. Sodium chloride

B. Calcium chloride

C. Potassium chloride

D. Carbon tetrachloride

(iv) The acid which can produce carbon from cane sugar, is:

A. Concentrated Hydrochloric acid

B. Concentrated Nitric acid

C. Concentrated Sulphuric acid

D. Concentrated Acetic acid

(v) The organic compound having a triple carbon-carbon covalent bond, is:

A. C₃H₄

B. C₃H₆

C. C₃H₈

D. C₄H₁₀

(b) State one relevant observation for each of the following reactions:

(i) Action of concentrated nitric acid on copper.

(ii) Addition of excess ammonium hydroxide into copper sulphate solution.

(iii) A piece of sodium metal is put into ethanol at room temperature.

(iv) Zinc carbonate is heated strongly.

(v) Sulphide ore is added to a tank containing oil and water, and then stirred or agitated with air.

(c) Write a balanced chemical equation for each of the following:

(i) Reaction of carbon powder and concentrated nitric acid.

(ii) Reaction of excess ammonia with chlorine.

(iii) Reaction of lead nitrate solution with ammonium hydroxide.

(iv) Producing ethane from bromo ethane using Zn / Cu couple in alcohol.

(v) Complete combustion of ethane.

(d) (i) Draw the structural formula for each of the following:

1. 2,2 dimethyl pentane

2. methanol

3. Iso propane

(ii) Write the IUPAC name for the following compounds:

1. acetaldehyde

2. acetylene

(e) State one relevant reason for each of the following:

(i) Graphite anode is preferred to platinum in the electrolysis of molten lead bromide.

(ii) Soda lime is preferred to sodium hydroxide in the laboratory preparation of methane.

(iii) Hydrated copper sulphate crystals turn white on heating.

(iv) Concentrated nitric acid appears yellow, when it is left for a while in a glass bottle.

(v) Hydrogen chloride gas fumes in moist air.

(f) Calculate:

(i) The amount of each reactant required to produce 750 ml of carbon dioxide, when two volumes of carbon monoxide combine with one volume of oxygen to produce two volumes of carbon dioxide.

2CO + O₂ → 2CO₂

(ii) The volume occupied by 80 g of carbon dioxide at STP.

(iii) Calculate the number of molecules in 4.4 gm of CO₂. [Atomic mass of C=12, O=16]

(iv) State the law associated in question no. (f)(i) above.

(g) Give one word or a phrase for the following statements:

(i) The chemical bond formed by a shared pair of electrons, each bonding atom contributing one electron to the pair.

(ii) Electrode used as a cathode in electrorefining of impure copper.

(iii) The substance prepared by adding other metals to a base metal in appropriate proportions to obtain certain desirable properties.

(iv) The tendency of an atom to attract electrons to itself when combined in a compound.

(v) The reaction in which carboxylic acid reacts with alcohol in the presence of conc. H₂SO₄ to form a substance having a fruity smell.

(h) Fill in the blanks from the choices given in brackets:

(i) The polar covalent compound in a gaseous state that does not conduct electricity is __________.

(carbon tetra chloride, ammonia, methane)

(ii) A salt prepared by displacement reaction is __________.

(ferric chloride, ferrous chloride, silver chloride)

(iii) The number of moles in 11gm of nitrogen gas is __________.

(0.39, 0.49, 0.29) [atomic mass of N=14]

(iv) An alkali which completely dissociates into ions is __________.

(ammonium hydroxide, calcium hydroxide, lithium hydroxide)

(v) An alloy used to make statues is__________.

(bronze, brass, fuse metal)

Answer:

(a) (i) D or Helium or He

(ii) B or Platinum or Pt

(iii) D or Carbon tetra chloride or CCl₄

(iv) C or Concentrated sulphuric acid or conc. H₂SO₄

(v) A or C3H4 or propyne or prop-1-yne or 1-propyne or 1 propyne or

OR

(b) (i) Reddish brown or brown or dark brown gas / fumes / vapour is liberated or evolved or released / blue solution / bluish solution formed / a gas with pungent smell is formed which turns potassium iodide paper brown. (for colour of gas – look for reddish brown or brown word)

Note:

a) only the word ‘blue’ is not accepted. The word ‘Solution’ is a must. No other

colour accepted.

b) A gas with pungent smell should be followed with a confirmatory test

(ii) Inky blue solution / deep blue solution is formed/ azure solution/ the precipitate or blue precipitate or pale blue precipitate dissolves, or is soluble / the precipitate or blue precipitate or pale blue precipitate (dissolves) forms inky blue/ deep blue solution.

Note:

The word ‘Solution is a must’. The word precipitate is not accepted if it is not supported by the word dissolves or soluble.

(iii) Bubbles of gas is released / or bubbles seen/ effervescence is seen/ fizz is formed/

colourless gas is released which extinguishes a burning splinter with a pop sound.

Note: colourless, odourless gas released should be followed by confirmatory test

(iv) A gas is released which turns lime water milky / a gas is released which is no effect / no change on potassium dichromate solution or potassium permanganate solution or a residue which is yellow when hot and white when cold is formed / white residue is left or formed. Note: acidified word is not a must but the word solution should be mentioned for potassium dichromate or potassium permanganate

(v) Froth / foam is produced/ lather is seen /bubbles are seen/ ore floats/ particles are seen floating/ lighter particles float/ heavy particles sink / gangue or matrix sink/ mud or soil sinks.

(c) (i) C + 4HNO₃ → CO₂ + 2H₂O + 4NO₂

(ii) 8NH₃ + 3Cl₂ → 6NH₄Cl + N₂

(iii) Pb(NO₃)₂ + 2NH₄OH → Pb(OH)₂ + 2NH₄NO₃

(iv)

(v) 2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O

(d) (i) 1. 2, 2 dimethyl pentane

(ii) IUPAC Name

1. ethanal / 1ethanal / ethan- 1-al

2. ethyne / 1 ethyne / eth- 1-yne

(e) (i) Since graphite anode is unaffected (by the reactive vapours of bromine) or does not react / Platinum is affected by (bromine vapours) or reacts with (bromine vapours)

(ii) Since soda lime is not deliquescent or does not attack glass or sodium hydroxide is deliquescent or CaO is a drying agent or CaO absorbs moisture.

(iii) As it loses water of crystallization/ loses water/loses definite number of water molecules/ turns anhydrous/ loses five molecules of water/ gets dehydrated

(iv) Concentrate nitric acid itself decomposes to form reddish brown or brown nitrogen dioxide gas which remains dissolved (imparts yellow colour to it). / or NO₂ gas formed dissolves in the acid to give yellow colour.

(v) As it is highly soluble in water. / high solubility/ absorbs moisture and forms mist/ affinity for water.

(f) (i) 2 mL of carbon monoxide produces 2 ml of carbon dioxide

750 mL of carbon dioxide produces = 750×2/2 = 750 mL

1 mL of oxygen produces 2ml of carbon dioxide

750 mL of carbon dioxide produces = 750 x 1/ 2 = 375 mL

Amount of carbon monoxide required is 750 mL and oxygen is 375 mL

(ii) 44 g of carbon dioxide occupies 22.4 L or 22400 mL

80 g of carbon dioxide occupies = 80 x 22.4 / 44 = 40.72 L

OR 80 x 22400/44 = 40720 mL

(iii) 44 g of CO₂ → 6.023 x 10²³

4.4 g of CO₂ → x

x = 4.4×6.023×10²³

= 6.023×10²²

(iv) When gases react, they do so in volumes which bear a simple whole number ratio to one another and to the volumes of the products, if gaseous, provided the temperature and pressure of the reacting gases and their products remain constant.

(g) (i) Covalent bond/ covalent

(ii) pure (thin block) of copper/ pure copper

(iii) Alloy

(iv) electronegativity/ electronegative property

(v) esterification

(h) (i) ammonia / NH₃

(ii) Ferrous chloride / FeCl₂ / Iron(II) chloride

(iii) 0.39/ or 11/28

(iv) Lithium hydroxide / calcium hydroxide/ or Formula accepted

(v) Bronze

Question 2:

(a) The following table represents the elements and the atomic number. With reference to this, answer the following using only the alphabets given in the table.

(i) Which element combines with hydrogen to form a basic gas?

(ii) Which element has an electron affinity zero?

(iii) Name the element, which forms an ionic compound with chlorine.

(b) Draw the electron dot diagram for the compounds given below. Represent the electrons by (.) and (x) in the diagram.

(i) Calcium oxide

(ii) Chlorine molecule

(iii) Water molecule

(c) Choose the correct word which refers to the process of electrolysis from A to E, to

match the description (i) to (iv):

A: Oxidation

B: Cathode

C: Anode

D: An electrolyte

E: Reduction

(i) Conducts electricity in aqueous or in molten state.

(ii) Loss of electrons takes place at anode.

(iii) A reducing electrode.

(iv) Electrode connected to the positive end or terminal of the battery.

Answer: (a) (i) Q / 7

(ii) R /10

(iii) P /13/ Al/ Aluminium

(b) (i)

(c) (i) D or an electrolyte

(ii) A or oxidation

(iii) B or cathode

(iv) C or anode

Question 3:

(a) Baeyer’s process is used to concentrate bauxite ore to alumina.

Give balanced chemical equations for the reaction taking place for its conversion from bauxite to alumina.

(b) Complete the following by selecting the correct option from the choices given:

(i) pH of acetic acid is greater than dilute sulphuric acid. So acetic acid contains

__________ concentration of H+ ions. (greater, same, low)

(ii) The indicator which does not change colour on passage of HCl gas is __________.

(methyl orange, moist blue litmus, phenolphthalein)

(iii) The acid which cannot act as an oxidizing agent is __________. (conc. H₂SO₄, conc. HNO₃, conc. HCl)

(c) Match the gases given in column I to the identification of the gases mentioned in column II:

Answer: (a)

(b) (i) low or less

(ii) Phenolphthalein

(iii) Concentrated HCl

(c) (i) D or turns moist lead acetate paper silvery black

(ii) C or turns reddish brown when it reacts with oxygen

(iii) B or turns lime water milky

(iv) A or turns acidified potassium dichromate solution green / B or turns lime water milky or A and B.

Question 4:

(a) Differentiate between the following pairs based on the information given in the brackets.

(i) Conductor and electrolyte (conducting particles)

(ii) Cations and anions (formation from an atom)

(iii) Acid and Alkali (formation of type of ions)

(b) Draw the structures of isomers of pentane.

(c) Hydrogen chloride gas is prepared in the laboratory using concentrated sulphuric acid and sodium chloride. Answer the questions that follow based on this reaction:

(i) Give the balanced chemical equation for the reaction with suitable condition(s) if any.

(ii) Why is concentrated sulphuric acid used instead of concentrated nitric acid?

(iii) How is the gas collected?

(iv) Name the drying agent not used for drying the gas.

Answer:

(a) (i) Conductor – conduction due to electrons.

Electrolyte – conduction due to ions.

(ii) Cations are formed by the loss of electrons from an atom / or oxidation of an atom / donating electrons.

Anions are formed by the gain of electrons by an atom / reduction of an atom/ accepting electrons.

(iii) Acid – forms H+ ions or hydronium (ions in solution) or H3O⁺ or hydrogen ions.

Alkali – forms hydroxyl (ion) or OH ^– (in solution) or hydroxide ion/hydroxide.

(b) (i) pentane

(ii) 2 methyl butane

(iii) 2, 2 dimethyl propane

(c) (i)

(ii) Concentrated H₂SO₄ is non-volatile / least volatile / less volatile/ has high boiling point and (hence can displace the more volatile HCl gas from the salt )

OR

Concentrated nitric acid is a volatile acid / low boiling point and

(will displace out itself along with HCl gas)

(iii) Upward displacement of air/ downward delivery / downward delivery of gas

(iv) Quicklime / calcium oxide / phosphorus pentoxide

Question 5:

(a) Distinguish between the following pairs of compounds using a reagent as a chemical test:

(i) Calcium nitrate and Zinc nitrate solution.

(ii) Ammonium sulphate crystals and Sodium sulphate crystals.

(iii) Magnesium chloride and Magnesium nitrate solution.

(b) Calculate the percentage of:

(i) Fluorine

(ii) Sodium and

(iii) Aluminium

in sodium aluminium fluoride [Na3AlF6], to the nearest whole number.

(c) (i) State the volume occupied by 40 gm of methane at STP, if its vapour density (V.D.) is 8.

(ii) Calculate the number of moles present in 160 gm of NaOH.

Answer:

(a) (i) Add NaOH / KOH / dil H2SO4 to both the solutions

Calcium nitrate forms a white precipitate which is insoluble in excess of NaOH while Zinc nitrate forms a gelatinous white precipitate soluble in excess.

With (dilute) Sulphuric acid … Calcium nitrate forms a white precipitate while Zinc nitrate does not form precipitate.

Or

With NH₄OH – Calcium nitrate no reaction or no precipitate while with Zinc nitrate it forms a (gelatinous white) precipitate soluble in excess / or white gelatinous precipitate with zinc nitrate.

(ii) Add any alkali / base

Ammonium sulphate produces a pungent colourless gas or colourless gas is released

which turns red litmus blue. While there is no reaction with sodium sulphate. Or no pungent gas released.

(iii) Add silver nitrate / lead nitrate solution to both / or perform brown ring test for nitrates

Magnesium chloride forms a whiteprecipitate while there is no reaction with magnesium nitrate.

Or

Magnesium chloride does not form a brown ring with Brown ring test while magnesium nitrate forms a brown ring.

(b) Molecular weight of Na₃AlF₆

= 23×3 + 27 + 19×6

= 210

(i) percentage of F = 114 x 100 / 210 = or 54.28% or 54.2 % or 54%

(ii) percentage of Na = 69×100/210 = or 32.85% or 32.8% or 33%

(iii) percentage of Al = 27 x 100 / 210 = or 12.85% or 12.8% or 13%

(c) (i) 16 g of CH₄ occupy = 22.4 L at STP

∴ 40 g of CH₄ occupy = 22.4 x 40 / 16 or 22400 x 40/16

= or 56 L or 56000 mL

(ii) Number of moles of NaOH = weight in grams / molecular weight

= 160 / 40 = 4 moles

Question 6:

(a) Identify the salts P, Q, R from the following observations:

(i) Salt P has a light bluish green colour. On heating, it produces a black coloured residue. Salt P produces brisk effervescence with dil. HCl and the gas evolved turns lime water milky, but no action with acidified potassium dichromate solution.

(ii) Salt Q is white in colour. On strong heating, it produces buff yellow residue and liberates reddish brown gas. Solution of salt Q produces chalky white insoluble precipitate with excess of ammonium hydroxide.

(iii) Salt R is black in colour. On reacting with concentrated HCl, it liberates a pungent greenish yellow gas which turns moist starch iodide paper blue black.

(b) Identify the substance underlined in each of the following:

(i) The electrode that increases in mass during the electro-refining of silver.

(ii) The acid that is a dehydrating as well as a drying agent.

(iii) The catalyst used to oxidize ammonia into nitric oxide.

(c) Copy and complete the following paragraph using the options given in brackets:

Alkenes are a homologous series of (i) __________ (saturated / unsaturated) hydrocarbons characterized by the general formula (ii) __________ (C_nH_2n+2 /C_nH_2n). Alkenes undergo (iii) __________ (addition / substitution) reactions and also undergo (iv) ________ (hydrogenation / dehydrogenation) to form alkanes.

Answer:

(a) (i) CuCO₃ or copper carbonate or copper(II) carbonate

(ii) Pb(NO₃)₂ or lead nitrate or lead(II) nitrate

(iii) MnO₂ or manganese dioxide or manganese (IV) oxide ….

(b) (i) cathode or negative electrode or reducing electrode or pure silver or pure Silver strip

or pure silver metal or pure Ag

(ii) concentrated sulphuric acid or conc. H₂SO₄

(iii) Platinum or Pt or Cu(copper) or Ni (Nickel) or Rh (Rhodium)

(c) (i) Unsaturated

(ii) C_nH_2n

(iii) Addition

(iv) Hydrogenation

Question 7:

(a) Write balanced chemical equations, for the preparation of the given salts (i) to (iii) by using the methods A to C respectively:

A: Neutralization

B: Precipitation

C: Titration

(i) Copper sulphate

(ii) Zinc carbonate

(iii) Ammonium sulphate

(b) Name the following elements:

(i) An alkaline earth metal present in group 2 and period 3.

(ii) A trivalent metal used to make light tools.

(iii) A monovalent non-metal present in fluorspar.

(c) An aqueous solution of nickel (II) sulphate was electrolyzed using nickel electrodes. Observe the diagram and answer the questions that follow:

(i) What do you observe at the cathode and anode, respectively?

(ii) Name the cation that remains as a spectator ion in the solution.

(iii) Which equation for the reaction at the anode is correct?

1. Ni → Ni²⁺ + 2e^–

2. Ni + 2e^– → Ni²⁺

3. Ni²⁺ → Ni + 2e^–

4. Ni²⁺ + 2e^– → Ni

Answer:

(a) (i) CuO + H₂SO₄ → CuSO₄ + H₂O

Or Cu(OH)₂ + H₂SO₄ → CuSO₄ + 2H₂O

Or CuCO₃ + H₂SO₄ → CuSO₄ + H₂O + CO₂

Or Cu(HCO₃)₂ + H₂SO₄ → CuSO₄ + 2H₂O + 2CO₂

(ii) ZnCl₂ + Na₂CO₃ → ZnCO₃ + 2NaCl

(or any soluble salts of zinc along with carbonates of sodium, potassium or ammonium as reactants)

(iii) 2NH₄OH + H₂SO₄ → (NH₄)₂SO₄ + 2H₂O Or 2NH₃ + H₂SO₄ → (NH₄)₂SO₄

(b) (i) Magnesium or Mg

(ii) Aluminium or Al

(iii) Fluorine or F

(c) (i) Cathode – silvery metal deposited or coated or sticks / nickel or metal is deposited or coated or sticks / silvery deposit/increases in size or mass Anode – Size decreases / reduction in mass / Anode dissolves/ Anode Diminishes/ Anode loses weight

(ii) Hydrogen ion or H+ or hydrogen

(iii) 1 or Ni → Ni²⁺ + 2e^– Or Ni – 2e^– → Ni²⁺

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