Question 1

Given below are two statements : Statement I: Aluminium upon reaction with NaOH forms [Al(OH)_6]^ 3- ion. Statement II: The geometry of ICl_4^-, ClO_3^- and IBr_2^- is square planar, pyramidal and lin

Accepted Answer

Statement I: Aluminium reacts with aqueous sodium hydroxide to form sodium tetrahydroxoaluminate(III) and liberates hydrogen gas. The reaction is given by: 2Al + 2NaOH + 6H_2O 2Na^+[Al(OH)_4]^- + 3H_2 The complex ion formed is [Al(OH)_4]^-, not [Al(OH)_6]^ 3- . Thus, Statement I is false. Statement II: For ICl_4^-, the central iodine atom has 7 valence electrons + 1 (from negative charge) = 8 electrons. It forms 4 sigma bonds with Cl atoms and has 2 lone pairs. The hybridization is sp^3d^2 and t

Question 2

Consider the following reactions Na _ 2 ~B _ 4 O _ 7 2 X + Y CuSO _ 4 + Y Non-Luminous flame Z + SO _ 3 2 Z +2 X + Carbon Luminous flame 2 Q + Na _ 2 ~B _ 4 O _ 7 + CO The oxidation states of Cu in Z

Accepted Answer

The given reactions describe the Borax Bead Test. When borax (Na_2B_4O_7 10H_2O) is heated, it first loses water and then melts to form a transparent glassy bead consisting of sodium metaborate (NaBO_2) and boric anhydride (B_2O_3). Na_2B_4O_7 2NaBO_2 (X) + B_2O_3 (Y) In the non-luminous (oxidizing) flame, B_2O_3 reacts with CuSO_4 to form copper(II) metaborate (Z), which is blue in color. CuSO_4 + B_2O_3 Non-Luminous Cu(BO_2)_2 (Z) + SO_3 In Cu(BO_2)_2, the oxidation state of Cu is +2. In the l

Question 3

It is noticed that Pb ^ 2+ is more stable than Pb ^ 4+ but Sn ^ 2+ is less stable than Sn ^ 4+ . Observe the following reactions. PbO _ 2 + Pb 2 PbO ; _ r G ^ (1) SnO _ 2 + Sn 2 SnO ; _ r G ^ (2) Iden

Accepted Answer

The stability of oxidation states in Group 14 is governed by the inert pair effect, which increases down the group. For Lead (Pb), the +2 oxidation state is more stable than the +4 state (Pb^ 2+ > Pb^ 4+ ). In the reaction PbO_2 + Pb 2PbO, Pb^ 4+ is being reduced to Pb^ 2+ and Pb^0 is being oxidized to Pb^ 2+ . Since the product contains the more stable oxidation state, the reaction is spontaneous, meaning _r G^ (1) For Tin (Sn), the +4 oxidation state is more stable than the +2 state (Sn^ 4+ >

Question 4

The correct statements from the following are : A. Ionic radii of trivalent cations of group 13 elements decreases down the group. B. Electronegativity of group 13 elements decreases down the group. C

Accepted Answer

Analyzing statements about Group 13 elements (B, Al, Ga, In, Tl): A. Ionic radii of M³⁺ cations: Down a group, more electron shells are added, so ionic radii increase, not decrease. FALSE B. Electronegativity: Generally decreases down the group, though Ga shows an anomaly with higher electronegativity than Al. The statement is approximately true but has exceptions. C. First ionization enthalpy: B (800.6 kJ/mol) is highest due to smallest size and highest nuclear charge density. Al (577.5), Ga (5

Question 5

Given below are two statements : Statement I : Elements ' X ' and ' Y ' are the most and least electronegative elements, respectively among N , As , Sb and P. The nature of the oxides X _ 2 O _ 3 and

Accepted Answer

For Statement I: Among N, As, Sb, P, the electronegativity order is N > P > As > Sb. Thus X = N (most electronegative) and Y = Sb (least electronegative). N_2O_3 is acidic (forms HNO₂ with water) and Sb_2O_3 is amphoteric (reacts with both acids and bases). Statement I is true. For Statement II: While BCl_3 is covalent and hydrolyzes in water to form B(OH)_3, the hydrolysis products are incorrect. In neutral aqueous medium, B(OH)_3 is formed. The tetrahedral [B(OH)_4]^- forms only in basic condi

Question 6

Consider the following reactions. PbCl _ 2 + K _ 2 CrO _ 4 ~A +2 KCl (Hot solution) A + NaOH B + Na _ 2 CrO _ 4 PbSO _ 4 +4 CH _ 3 COONH _ 4 ( NH _ 4 )_ 2 SO _ 4 + X In the above reactions, A , B and

Accepted Answer

Reaction 1: PbCl_2 + K_2CrO_4 PbCrO_4 + 2KCl A = PbCrO_4 (lead chromate) Reaction 2: PbCrO_4 + 4NaOH Na_2[Pb(OH)_4] + Na_2CrO_4 B = Na_2[Pb(OH)_4] (sodium tetrahydroxoplumbate) Reaction 3: PbSO_4 + 4CH_3COONH_4 (NH_4)_2SO_4 + (NH_4)_2[Pb(CH_3COO)_4] X = (NH_4)_2[Pb(CH_3COO)_4] (ammonium tetraacetatoplumbate)

Question 7

Given below are two statements : Statement I : The number of pairs among [ SiO _ 2 , CO _ 2 ], [ SnO , SnO _ 2 ], [ PbO , PbO _ 2 ] and [ GeO , GeO _ 2 ], which contain oxides that are both amphoteric

Accepted Answer

Statement I: Checking amphoteric nature of oxide pairs: [SiO_2, CO_2]: Both acidic (non-metal oxides) [SnO, SnO_2]: Both amphoteric [PbO, PbO_2]: PbO is amphoteric but PbO_2 is predominantly acidic/oxidizing [GeO, GeO_2]: Both amphoteric (Ge is metalloid) 2 pairs have both oxides amphoteric. Statement I is true. Statement II: BF_3 has B with 6 valence electrons (electron deficient), acts as Lewis acid, forms BF_3 NH_3 adduct, has sp^2 hybridization giving trigonal planar geometry. Statement II i

p Block Elements (Group 13 & 14) — Previous Year Questions & Solutions