SOLUTIONS ICSE CHEMISTRY 2025

Question 1.

i.(a) Sulphur dioxide

ii.(b) C5H2

iii.(a) Copper

iv.(d) C3H8

v.(c) Oxidising agent

vi.(c) (A) is true but (R) is false.

vii.(b) Haematite

viii.(d) A 2,6 B 2,8,7

ix.(a) CH4, C2H6, C3H8,

x.(a) Both (A) and (R) are true, and (R) is the correct explanation of (A).

xi.(c) CI1- & K1+

xii.(c) Sodium sulphate + Lead nitrate

xiii.(d) The number of copper (II) ions in the electrolyte decreases.

xiv.(c) Z

xv.(b) 40 cm3

Question 2.

i.(a) Hot water

(b) AlN + 3H2O → Al(OH)3 + NH3

(c) Calcium oxide

(d) Drying agent

(e) Ammonia being highly soluble in water, dissolved in water

ii.(a) Spurious alcohol

(b) Basic salt

(c) Isomers

(d) Electronegativity

(e) Polar covalent bond

iii.(a) Copper nitrate

(b) Roasting

(c) Molten sodium chloride

(d) Ag →Ag1+ +e

(e) sodium zincate

iv.(a) 3. Iron

(b) 5. Platinum

(c) 1. Vanadium Pentoxide

(d) 2. Nickel

(e) 4. Concentrated Sulphuric acid

v.(a)

2-methylpropene Butanal

CH3

(b)

1,1,2,2-tetrachloroethane

Butanoic acid

2-pentene

SECTION B (40 Marks)

Question 3.

(a) X belongs to period 3

(b) XY2

ii.(a) Anode is the oxidising electrode as the anions lose electron and get oxidized at the anode.

(b) Graphite electrodes are preferred in the electrolysis of molten lead bromide as graphite is an inert electrode that doesn't react with the electrolyte or the products of electrolysis, ensuring efficient and effective electrolysis.

iii.(a) Mass of sulphuric acid = 2×98×6024=490 𝑔𝑚

(b) The volume of sulphur dioxide gas liberated at S.T.P. = 22.4×6024=56𝐿

iv.(a) White precipitate

(b) Yellow residue

(c) Moist starch iodide paper turns blue black

Question 4.

i.(a) The vapour density of' the gas G = 450150=3

(b) RMM = 2VD = 6

ii.(a) CH3COONa + NaOH → Na2CO3 + CH4

(b) 2CH3COOH + Mg → (CH3COO)2Mg + H2

iii.(a) Nitrogen dioxide

(b) Nitrogen

(c) Hydrogen sulphide

iv.(a) The valency of element 'G' : 3

(b) E

(c) MP2

Question 5.

i.(a) Cl

(b) Ne

ii.(a) Nitrogen

(b) Pinkish brown

iii.(a) (NH4)2CO3 + 2HCl → 2NH4Cl + CO2 + H2O

(b) S + 6HNO3 → H2SO4 + 6NO2 + 2H2O

(c) C + 2H2SO4→ CO2 + 2SO2 + 2H2O

iv.(a) White precipitate

(b) 1. Precipitate dissolved

2. Precipitate remains the same

Question 6.

i.(a) Amphoteric

(b) CuO

(c) Na2O

ii.(a) C

(b) D & F

(c) A & B

iii.

C : O : H = 47.412∶ 42.116∶ 10.51

= 3.95 : 2.63 : 10.5

= 3.952.63 ∶ 2.632.63 ∶ 10.52,63 1.5 : 1 : 4

= 3 : 2 : 8

Empirical formula : C3O2H8

Empirical weight = 36 + 32 + 8 = 76

Empirical mass = Relative Molecular mass =76

⸫ Molecular Formula = Empirical formula = C3O2H8

Question 7.

i.(a) Nitrogen dioxide

(b) Cu + 4HNO3 → Cu(NO3)2 + 2NO2 + 2H2O

ii.(a) Baeyer’s Process

(b) 2Al(OH)3 Δ→ Al2O3 + 3H2O

iii.(a)

Mg → Mg2+ + 2 Cl → Mg2+ (Cl1-)2

(b) → H ─ Cl

(c) H H

H N H → H─N→H

H H

iv.

(a) To make water a conducting solution, so that water ionizes to form ions.

(b) 2H1+ + 2e → H2

(c) Bubbles of colourless gas

Question 8.

i.(a) At same temperature & pressure, equal volume of gases have equal number of molecules.

(b) A bond formed by sharing of electrons, where both the shared electrons are contributed by one of the combining atoms and are shared between both the atoms is called a co-ordinate bond.

ii.(a) Ammonium chloride when heated with alkali produces pungent smelling gas which turns moist red litmus paper blue, nut sodium chloride with alkali produces no gas.

(b) With excess sodium hydroxide solution, zinc nitrate solution produces colourless solution ( white precipitate formed with little NaOH solution dissolves in excess), whereas calcium nitrate with excess sodium hydroxide solution produces white precipitate (white precipitate formed with little NaOH solution is in soluble in excess)

iii.(a) SO2

(b) NCl3

(c) PbO

iv.(a) R- Precipitation

(b) S─ Direct combination

(c) Q- Neutralisation by titration