Vardaan Learning Institute

Ans: (d) Fe (Iron)
Iron reacts only with steam (red hot iron + steam). It does not react with cold or hot water.

Ans: (c) $Fe_3O_4$
$3Fe + 4H_2O(g) \rightarrow Fe_3O_4 + 4H_2$.

Ans: (d) Y is a non-metal and Z is a metal
Y (2, 8, 7) has 7 valence electrons $\rightarrow$ Chlorine (Non-metal).
Z (2, 8, 2) has 2 valence electrons $\rightarrow$ Magnesium (Metal).

Ans: (b) Electrical conductivity in solid state
In solid state, ions are not free to move, so they do not conduct electricity.

Ans: (a) Zinc is more reactive than iron
This uses the principle of sacrificial protection. Zinc corrodes in preference to iron.

Ans: (d) Iodine
Iodine is a non-metal but it has a lustrous (shiny) surface.

Ans: (a) Ductility
Ductility is the property of metals to be drawn into thin wires.

Ans: (d) AgNO3 solution and copper metal
Copper is more reactive than Silver, so it displaces Silver from Silver Nitrate solution.

Ans: (c) Zinc is more reactive than tin
If coated with Zinc, it would react with organic acids in food. Tin is less reactive and safe.

Ans: (a) Calcium
Calcium reacts with oxygen to form Calcium Oxide (High MP) which dissolves in water to form Calcium Hydroxide (Lime water).

Ans: (a) Both A and R are true and R is the correct explanation of A.
ZnO reacts with HCl (acid) to form $ZnCl_2$ and with NaOH (base) to form $Na_2ZnO_2$.

Ans: (c) A is true but R is false.
Gold and Platinum are found in native state because they are LEAST reactive metals, not highly reactive.

Ans: (a) Both A and R are true and R is the correct explanation of A.
Strong electrostatic forces of attraction between oppositely charged ions require high energy to break.

Ans: (b) Both A and R are true but R is not the correct explanation of A.
Metals form basic oxides (True) and Non-metals form acidic oxides (True), but R explains non-metals, not why metals form basic oxides (which is due to donation of electrons).

(i) Arrangement of metals in decreasing order of their reactivity.
(ii) $Na > Mg > Zn > Fe$.
(iii) Calcium reacts with water to form hydrogen gas bubbles which stick to the surface of the metal, making it float.

Roasting: Heating sulphide ore in excess air. e.g., $2ZnS + 3O_2 \rightarrow 2ZnO + 2SO_2$.
Calcination: Heating carbonate ore in limited air. e.g., $ZnCO_3 \xrightarrow{\Delta} ZnO + CO_2$.

(i) $Na$ (2,8,1) has 1 dot. $Cl$ (2,8,7) has 7 dots.
(ii) Na transfers 1 electron to Cl. $Na \rightarrow Na^+ + e^-$, $Cl + e^- \rightarrow Cl^-$.
(iii) Ions: Sodium cation ($Na^+$) and Chloride anion ($Cl^-$).

Reduction of iron(III) oxide with Aluminium powder which is highly exothermic.
$Fe_2O_3(s) + 2Al(s) \rightarrow 2Fe(l) + Al_2O_3(s) + \text{Heat}$.
Use: Joining railway tracks or cracked machine parts.

(i) Metals like Al form a protective oxide layer ($Al_2O_3$) on their surface which prevents further corrosion/reaction.
(ii) It is easier to obtain metal from its oxide (by reduction) than from its carbonate or sulphide. Hence, ores are first converted to oxides.
(iii) Copper is a good conductor of heat and does not react with steam/hot water, whereas steel (iron) reacts with steam to corrode.

(i) Mercury (Hg).
(ii) Graphite (Carbon allotrope).
(iii) Sodium is highly reactive and reacts vigorously with oxygen and moisture in air. Kerosene cuts off contact with air.

(i) Electrolytic Refining.
(ii) (Student diagram of Electrolysis).
(iii) Anode: $Cu \rightarrow Cu^{2+} + 2e^-$ (Oxidation of impure copper). Cathode: $Cu^{2+} + 2e^- \rightarrow Cu$ (Reduction/Deposition of pure copper).
(iv) Insoluble impurities settle at the bottom of the anode, called anode mud.

(i) Homogeneous mixture of two or more metals (or a metal and non-metal). Prepared by melting primary metal and dissolving others.
(ii) (a) Brass: Cu + Zn (b) Bronze: Cu + Sn (c) Solder: Pb + Sn.
(iii) Alloys have higher resistivity than constituent metals and do not oxidise (burn) readily at high temperatures.

(i) Metal B (Displaces Iron).
(ii) $B > A > C > D$. (Logic: B > Fe; A < Fe but tested with FeSO4 only? Actually from NCERT table: B is most reactive, A is second, C is third, D is least).
(iii) Metal D (Least reactive, likely to be Silver/Gold/Platinum). Or Metal C (Displaces Cu, less than Fe... could be Pb?). Silver is usually D.

(i) Hydrated Iron(III) Oxide, $Fe_2O_3 \cdot xH_2O$.
(ii) Painting, Oiling/Greasing, Galvanization, Chrome plating.
(iii) Silver reacts with Sulphur in air to form black Silver Sulphide ($Ag_2S$).