Complete ICSE Class X Chemistry 2023 question paper with accurate, step-by-step solutions.
(Attempt all questions from this section)
An element in period 3, whose electron affinity is zero:
(d) Argon
Explanation:
Argon belongs to period 3. It is an inert element and its octet is complete hence, it’s electron affinity is zero.
An element with the largest atomic radius among the following is:
(a) Carbon
(b) Nitrogen
(c) Lithium
(d) Beryllium
c. Lithium
Explanation:
The given elements belong to the second period and Lithium is the first element of second period. Atomic size decreases from left to right in a period hence, Lithium will have the largest atomic radius.
The compound that is not an ore of aluminium:
(c) Fluorspar
Explanation:
Fluorspar is calcium fluoride [CaF2], not an ore of aluminium.
The other three options are ores of aluminium:
The vapour density of CH₃OH is …………… (At. Wt. C=12, H=1, O=16)
c. 16
Explanation:
Molecular mass of methyl alcohol [CH3OH] = 12 + 3(1) + 16 + 1 = 32
Vapour density = molecular mass ÷ 2
= 32 ÷ 2
= 16
Which of the following reactions takes place at the anode during the electroplating of an article with silver?
(a) Ag − 1e− ⟶ Ag1+
Explanation:
Anode reaction – Ag − 1e− ⟶ Ag1+
The metallic hydroxide which forms a deep inky blue solution with excess ammonium hydroxide solution is:
(b) Cu(OH)2
Explanation:
Cu(OH)2 reacts with a solution of excess ammonium hydroxide to form a deep blue solution of tetrammine copper [II] sulphate.
Cu(OH)2 + (NH4)2SO4 + 2NH4OH ⟶ [Cu(NH3)4]SO4 + 4H2O
An example of a cyclic organic compound is:
(d) Benzene
Explanation:
In benzene, six carbon atoms form a ring structure and there are three single and three double bonds between the carbon atoms. Hence, benzene is a cyclic compound.
In the laboratory preparation, HCl gas is dried by passing through:
(b) Concentrated sulphuric acid
Explanation:
Concentrated Sulphuric acid only removes the moisture content of HCl gas but does not react with it. Hence, it is used as a drying agent for HCl gas.
The nitrate which on thermal decomposition leaves behind a residue which is yellow when hot and white when cold:
(d) Zinc nitrate
Explanation:
On heating, zinc nitrate decomposes to form zinc oxide, nitrogen dioxide, and oxygen.
2\mathrm{Zn(NO_3)_2} \xrightarrow{\Delta} 2\mathrm{ZnO} + 4\mathrm{NO_2} + \mathrm{O_2}
The solid residue is zinc oxide (ZnO), which is yellow when hot and white when cold.
The salt formed when concentrated sulphuric acid reacts with KNO3 above 200°C:
(a) K2SO4
Explanation:
Above 200°C, potassium nitrate reacts with concentrated sulphuric acid to form potassium sulphate and nitric acid.
The balanced equation is:
2\mathrm{KNO_3} + \mathrm{H_2SO_4} \xrightarrow{>200^\circ\mathrm{C}} \mathrm{K_2SO_4} + 2\mathrm{HNO_3}
Therefore, the salt formed is potassium sulphate (K2SO4).
The property exhibited by concentrated sulphuric acid when it is used to prepare hydrogen chloride gas from potassium chloride: [1]
(d) Non-volatile acid property
Explanation:
Concentrated sulphuric acid has a high boiling point and is non-volatile. It displaces the more volatile hydrogen chloride from potassium chloride.
The hydrocarbon formed when sodium propanoate and soda lime are heated together:
b. Ethane
Explanation:
Heating sodium propanoate with soda lime causes decarboxylation. The alkane formed has one carbon atom fewer than the original carboxylate.
\mathrm{CH_3CH_2COONa}+\mathrm{NaOH}\xrightarrow{\mathrm{CaO},\,\Delta}\mathrm{C_2H_6}+\mathrm{Na_2CO_3}
Sodium propanoate has three carbon atoms; the hydrocarbon product, ethane, has two.
The acid which does not form acid salt by a basic radical:
(d) CH3COOH
Explanation:
Acetic acid is monobasic: only the hydrogen of its carboxyl (–COOH) group is replaceable by a basic radical.
Replacing this hydrogen forms a normal salt, such as sodium acetate (CH3COONa). No replaceable acidic hydrogen remains to form an acid salt.
The general formula of hydrocarbons with single covalent bonds is:
(a) CnH2n+2
Explanation:
The open-chain saturated hydrocarbons are called alkanes. They contain only single covalent bonds and have the general formula CnH2n+2, where n is the number of carbon atoms.
The indicator which changes to pink colour in an alkaline solution is:
(d) Phenolphthalein
Explanation:
Phenolphthalein is colourless in acidic and neutral solutions. It turns pink in an alkaline solution.
Match the Column A with Column B:
| Column A | Column B |
|---|---|
| (a) Sodium chloride | 1. has two shared pair of electrons |
| (b) Methane | 2. has high melting and boiling points |
| (c) Hydrogen chloride gas | 3. a greenhouse gas |
| (d) Oxidation reaction | 4. has low melting and boiling points |
| (e) Water | 5. Zn − 2e− ⟶ Zn2+ |
| 6. S + 2e− ⟶ S2− |
(a)–2: Sodium chloride — has high melting and boiling points.
(b)–3: Methane — a greenhouse gas.
(c)–4: Hydrogen chloride gas — has low melting and boiling points.
(d)–5: Oxidation reaction — Zn − 2e− → Zn2+.
(e)–1: Water — has two shared pairs of electrons.
The following sketch illustrates the process of conversion of Alumina to Aluminium: [5]
Study the diagram and answer the following:
(a) Name the constituent of the electrolyte mixture which has a divalent metal in it.
(b) Name the powdered substance ‘X’ sprinkled on the surface of the electrolyte mixture.
(c) What is the name of the process?
(d) Write the reactions taking place at the electrodes ‘Y’ (anode) and ‘Z’ (cathode) respectively.
(a) Fluorspar, CaF2.
(b) Powdered coke.
(c) Hall–Héroult process.
(d) At Y (anode):
2O2− → O2 + 4e−
At Z (cathode):
Al3+ + 3e− → Al
Fill in the blanks with the choices given in the brackets:
(a) Metals are good …………… [oxidizing agents /reducing agents]
(b) Non-polar covalent compounds are …………… [good / bad] conductors of heat and electricity.
(c) Higher the pH value of a solution, the more is …………… [acidic / alkaline] it is.
(d) …………… [Silver chloride / Lead chloride] is a white precipitate that is soluble in excess of Ammonium hydroxide solution.
(e) Conversion of ethene to ethane is an example of …………… . [hydration / hydrogenation]
(a) Metals are good reducing agents
(b) Non-polar covalent compounds are bad conductors of heat and electricity.
(c) Higher the pH value of a solution, the more alkaline it is.
(d) Silver chloride is a white precipitate that is soluble in excess of Ammonium hydroxide solution.
(e) Conversion of ethene to ethane is an example of hydrogenation.
State the terms/process for the following:
(a) The energy released when an atom in the gaseous state accepts an electron to form an anion.
(b) Tendency of an element to form chains of identical atoms.
(c) The name of the process by which Ammonia is manufactured on a large scale.
(d) A type of salt formed by partial replacement of hydroxyl radicals with an acid radical.
(e) The ratio of the mass of a certain volume of gas to the same volume of hydrogen measured under the same conditions of temperature and pressure.
(a) Electron affinity
(b) Catenation
(c) Haber’s process
(d) Basic salt
(e) Vapour density
Give the structural formulas and IUPAC names as directed:
(a) Give the structural formula of the following organic compounds:
(b) Give the IUPAC name of the following organic compounds:
(a) Structural formulas:
1. 2-chlorobutane
2. Methanal
3. But-2-yne
(b) IUPAC names:
(Attempt any four questions)
Identify the cation in each of the following cases:
(a) Ammonium hydroxide solution when added to Solution B gives a white precipitate which does not dissolve in excess of ammonium hydroxide solution.
(b) Sodium hydroxide solution when added to Solution C gives a white precipitate which is insoluble in excess of sodium hydroxide solution.
(a) Lead(II) ion, Pb2+.
(b) Calcium ion, Ca2+.
Fill in the blanks by choosing the correct answer from the brackets:
(a) During electrolysis, the compound …………… in its molten state liberates reddish brown fumes at the anode. [NaCl/PbBr2]
(b) The ion which could be discharged most readily during electrolysis is …………… [Fe2+/Cu2+]
(a) PbBr2 (lead bromide).
(b) Cu2+
Arrange the following as per the instruction given in the brackets:
(a) Al, K, Mg, Ca (decreasing order of its reactivity)
(b) N, Be, O, C (increasing order of non-metallic character)
(c) P, Si, F, Be (decreasing order of valence electrons)
(a) K > Ca > Mg > Al
(b) Be < C < N < O
(c) F > P > Si > Be
Complete and balance the following equations:
(a) NH4Cl + Ca(OH)2 →
(b) CuSO4 + NH4OH →
(c) Cu + Conc. HNO3 →
(a) 2NH4Cl + Ca(OH)2 → CaCl2 + 2NH3 + 2H2O
(b) CuSO4 + 2NH4OH → (NH4)2SO4 + Cu(OH)2↓
(c) Cu + 4HNO3 (conc.) → Cu(NO3)2 + 2NO2 + 2H2O
State a relevant reason for the following: [2]
(a) Hydrogen chloride gas cannot be dried over quick lime.
(b) Ammonia gas is not collected over water.
(a) Quicklime (CaO) reacts with hydrogen chloride, forming calcium chloride and water. It would absorb the gas itself, so it cannot be used to dry HCl.
CaO + 2HCl → CaCl2 + H2O
(b) Ammonia is highly soluble in water and would dissolve instead of being collected.
Identify the alloy in each case from the given composition:
(a) Aluminium, magnesium, manganese, copper
(b) Iron, nickel, chromium, carbon
(a) Duralumin
(b) Stainless steel
Ethane burns in oxygen according to the chemical equation:
2C2H6 + 7O2 → 4CO2 + 6H2O
If 80 ml of ethane is burnt in 300 ml of oxygen, find the composition of the resultant gaseous mixture when measured at room temperature.
[By Lussac’s law]
2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O
2 vol. : 7 vol. → 4 vol.
(i) To calculate the volume of CO₂ formed:
C₂H₆ : CO₂
2 vol. : 4 vol.
80 ml : x
∴ x = (4/2) × 80 = 160 ml
Hence, volume of carbon dioxide formed = 160 ml
(ii) To calculate the volume of unused O₂:
C₂H₆ : O₂
2 vol. : 7 vol.
80 ml : x
∴ x = (7/2) × 80 = 280 ml
Unused oxygen = 300 − 280 = 20 ml
Hence, volume of unused oxygen = 20 ml
Therefore, the resultant gaseous mixture consists of 160 ml of carbon dioxide and 20 ml of unused oxygen.
The following questions are pertaining to the laboratory preparation of Ammonia gas from Magnesium nitride:
(a) Write a balanced chemical equation for its preparation.
(b) Why is this method seldom used?
(c) How do you identify the gas formed?
(a) Mg3N2 + 6H2O → 3Mg(OH)2 + 2NH3
(b) Magnesium nitride is expensive, so this method is seldom used.
(c) Ammonia turns moist red litmus paper blue. It also forms dense white fumes of ammonium chloride when a glass rod dipped in concentrated hydrochloric acid is brought near the gas.
NH3 + HCl → NH4Cl
Write one use of the following alloys:
(a) Bronze
(b) Fuse metal
(a) Bronze is used for making statues.
(b) Fuse metal is used for making electrical fuse wires.
Draw the electron dot structure for the following:
(a) Ammonium ion
(b) A molecule of nitrogen
[At. No.: N=7, H=1]
(a) Ammonium ion:
(b) Nitrogen molecule:
Give a balanced chemical equation for the following conversions with conditions:
(a) Ethene from ethanol
(b) Ethyne from calcium carbide
(c) Monochloromethane from methane
(a) Ethene from ethanol:
\mathrm{C_2H_5OH \xrightarrow[\text{excess}]{170^\circ\mathrm{C},\ conc.\ H_2SO_4} C_2H_4 + H_2O}
(b) Ethyne from calcium carbide:
CaC₂ + 2H₂O → C₂H₂ + Ca(OH)₂
(c) Monochloromethane from methane:
\mathrm{CH_4 + Cl_2 \xrightarrow{\Delta,\ diffused\ sunlight} CH_3Cl + HCl}
Study the following observations and name the anions present in each of the reactions.
(a) When a crystalline solid ‘P’ is warmed with concentrated H2SO4 and copper turnings a reddish brown gas is released.
(b) When few drops of dilute sulphuric acid is added to Salt ‘R’ and heated, a colourless gas is released which turns moist lead acetate paper silvery black.
(c) When few drops of barium nitrate solution is added to the salt solution ‘Q’, a white precipitate is formed which is insoluble in HCl.
(a) Nitrate ion, NO₃⁻.
(b) Sulphide ion, S²⁻.
(c) Sulphate ion, SO₄²⁻.
Define / State:
(a) Electronegativity.
(b) Gay-Lussac’s law of combining volumes.
(a) Electronegativity is the tendency of an atom in a molecule to attract the shared pair of electrons towards itself.
(b) When gases react, they do so in volumes that bear a simple whole-number ratio to one another and to the volume of gaseous products, provided all volumes are measured at the same temperature and pressure.
The Empirical formula of an organic compound is CHCl2.
If its relative molecular mass is 168, what is its molecular formula?
[At. Wt. C = 12, H = 1, Cl = 35.5]
Empirical formula mass = 12 + 1 + 2(35.5) = 84.
n = 168 ÷ 84 = 2.
Therefore, molecular formula = (CHCl₂)₂ = C₂H₂Cl₄.
Choose the substances given in the box below to answer the following questions:
| Iron | Magnesium sulphite | Zinc | Sodium sulphide |
| Lead | Ferric chloride | Copper | Ferrous sulphate |
(a) The metal that will not produce hydrogen gas when reacted with dilute acids.
(b) The compound that will produce sulphur dioxide gas when reacted with dilute HCl.
(c) The solution of this compound produces dirty green precipitate with NaOH.
(a) Copper
(b) Magnesium Sulphite
(c) Ferrous Sulphate
State one relevant observation for each of the following:
(a) To the copper nitrate solution, initially few drops of sodium hydroxide solution is added and then added in excess.
(b) Burning of ammonia in excess of oxygen.
(c) Dry ammonia gas is passed over heated PbO.
(a) A light-blue precipitate of copper(II) hydroxide is formed. It remains insoluble in excess sodium hydroxide solution.
(b) Ammonia burns with a greenish-yellow flame, forming nitrogen and water vapour.
(c) The buff-yellow lead(II) oxide is reduced to grey metallic lead.
Name the following:
(a) Organic compounds with same molecular formula but different structural formula.
(b) Group of organic compounds where the successive members follow a regular structural pattern, successive compounds differ by a ‘CH2’ group.
(a) Isomers.
(b) Homologous series.
Give a reason for each:
(a) Ionisation potential decreases down a group.
(b) Ionic compounds do not conduct electricity in the solid state.
(a) Down a group, atomic size and shielding increase; therefore the outer electron is held less strongly and is removed more easily.
(b) In a solid ionic compound, the ions are fixed in the crystal lattice and cannot move to carry electric current.
Calculate:
(a) The percentage of phosphorus in the fertilizer super phosphate Ca(H2PO4)2 correct to 1 decimal point.
(b) Write the empirical formula of C8H18
[At. Wt. H=1, P=31, O=16, Ca=40]
(a) Formula mass of Ca(H₂PO₄)₂ = 40 + 2[2(1) + 31 + 4(16)] = 234.
Mass of phosphorus = 2 × 31 = 62.
\frac{62}{234}\times100=26.5\%
(b) C₈H₁₈ = (C₄H₉)₂.
Empirical formula = C₄H₉.
Answer the following with reference to the electrolytic refining of copper:
(a) What is used as the anode?
(b) Where is pure copper deposited?
(c) Write the cathode reaction.
(a) A block of impure copper is used as the anode.
(b) Pure copper is deposited on the cathode, which is a thin sheet of pure copper.
(c) Cu²⁺ + 2e⁻ → Cu
Arrange the following according to the instructions given in brackets:
(a) C2H2, C3H6, CH4, C2H4 (In the increasing order of the molecular weight)
(b) Cu2+, Na+, Zn2+, Ag+ (The order of Preferential discharge at the cathode)
(a) Molecular weight of C2H2 = 2[12] + 2[1] = 26
Molecular weight of C3H6 = 3[12] + 6[1] = 42
Molecular weight of CH4 = 12 + 4[1] = 16
Molecular weight of C2H4 = 2[12] + 4[1] = 28
Hence, increasing order of molecular weights is :
CH4 < C2H2 < C2H4 < C3H6
(b) Ag+, Cu2+, Zn2+, Na+
Differentiate between the following pairs based on the criteria given in the brackets:
(a) Cane sugar and hydrated copper sulphate [using concentrated H2SO4]
(b) Sulphuric acid and hydrochloric acid [type of salts formed]
(a) Cane sugar is dehydrated by concentrated sulphuric acid and turns black due to carbon formation:
\mathrm{C_{12}H_{22}O_{11}\xrightarrow{\text{conc. }H_2SO_4}12C+11H_2O}
Hydrated copper(II) sulphate changes from blue to white anhydrous copper(II) sulphate.
(b) Sulphuric acid forms sulphate salts, whereas hydrochloric acid forms chloride salts.
Convert the following reactions into a balanced chemical equation:
(a) Ammonia to nitric oxide using oxygen and platinum catalyst.
(b) Sodium hydroxide to sodium sulphate using sulphuric acid.
(c) Ferrous sulphide to hydrogen sulphide using hydrochloric acid.
(a) \mathrm{4NH_3+5O_2\xrightarrow[\ 800^\circ C\ ]{Pt}4NO+6H_2O}
(b) 2NaOH + H₂SO₄ → Na₂SO₄ + 2H₂O
(c) FeS + 2HCl → FeCl₂ + H₂S↑
Choose the answer from the list which fits in the description:
[CCl4, PbO, NaCl, CuO, NH4Cl]
(a) A compound which undergoes thermal dissociation.
(b) An amphoteric oxide.
(c) A compound which is a non-electrolyte.
(a) NH₄Cl
(b) PbO
(c) CCl₄
No questions match these filters.
