JEE Questions for Chemistry Class 12 P Block Elements Quiz 5 - MCQExams.com

Due to high heat of hydration and low heat of dissociation, the oxidising power of flourine is high.
Flourine is smallest in size, there is considerable repulsion in the non-bonding electrons. So, bond dissociation of F₂ will be low.

Hydrides of N, O and F have ability to form extensive intramolecular H bonding due to their small size and high electronegativity of elements.

HClO₄ > HBrO₄ > HIO₄.

Acidic strgth of oxyacids of halogen.

Hydration of F = -515kJ/mol.

F₂ is most electronegative. It has greater electron – electron repulsion.

Enthalapy of dissociation of F₂ is lower than Cl₂.

Flourine is more electronegative than chlorine hence, it can displace Cl from HCl while chlorine cannot displace flourine from HF.

   HF + Cl₂ → F₂ + HCl.

Upper halogen can replace lower halogen from their compound solution.

Flourine exhibits –1 oxidation state only because of its strong electronegative character.

Bond dissociation energy

Cl₂ > Br₂ >I₂

Bond dissociatiom enthalpy – Cl₂ > Br₂ >I₂ 

Pseudohalide ions cobine together to form Interpseudohalogen compound.

Aqua regia is a mixture of 3 points concentrated HCl + 1 part concentrated HNO₃.

Pseudohalide – combination of more than electronegative atoms have one unit negative charge example: OCN^–, CN^–.

Polyhalide ion formed by reaction of halogen among themselves. Example:I₃^–, BrI₂^–.

Palladium, platinum ans iridium are not attached by strong acids. So, known as noble metals.

He is less soluble than Nitrogen in blood, hence He – O₂ mixture is used by deep sea drivers in preference to N₂ – O₂ mixture.

Helium is less soluble in blood than Nitrogen. So, helium oxygen mixture is life saving mixture for asthma patients.

First ionisation energy and molecule diameter of Xenon and oxygen are quite similar. Since oxygen combines with PtF₆, so xenon also forms similar compound with PtF₆.

Some noble gases are adsorbed on coconut charcoal. Some can’t . So, coconut charcoal can be used to separate different.

Dipole induced dipole attraction is involved in clathrate formation.

Fischer Ringe method – used to separate noble gas mixture from air.

90% CaC₂ and 10% CaCl₂ is used for this purpose.

P₄+3NaOH + 3H₂O → PH₃+3NaH₂PO₂ In phosphine (PH₃),phosphorus has been reduced from zero to – 3 and in sodium hypophosphite (NaH₂PO₂), phosphorus has been oxidized from zero to +1.

Metallic character increases down the group as the electropositive character increases or ionization energy decreases.

E.N. increases from left to right across a period and from bottom to top up the group. Therefore, the order of increasing E.N. is Si < P < C < N.

Pyrophosphoric acid H₄P₂O₄ obtained by condensing two molecules of H₃PO₄ by losing one H₂O molecule, contains one P-O-P bond, four P-OH bonds and two P = 0 bonds.

Both white and red phosphorus are not soluble in CS₂. Only white P is soluble.

H₄P₂O₆ (hypophosphoric acid ) forms only two series of salts i.e, Na₂H₂P₂O₆ and Na₂P₂O₆. The salt Na₃HP₂O₆ is not formed at all.

NCl₃ is a volatile highly explosive liquid (m.p. -40ºC and b. p. 71ºC).

Due to the absence of H-Bonding, PH₃ has the lowest b.p.

In case of nitrogen, d- orbitals are not available

The element having electronic configuration as [Ne] 3s² 3sp³ will have highest ionization energy because it has more stable half filled electronic configuration and also is smaller in size than that of the element having electronic configuration as [Ar] 3d¹⁰ 4s² 4p³.

Valence shell electronic configuration of P in the ground state = 3s² 3p³ and in excited state = 3s¹ 3p³ 3d¹. As there are three and five unpaired electrons available in the valence shell , P generally shows a covalency of three and five in e.g. PCl₃ and PCl₅ respectively.

Amongst B, C, N and O, nitrogen has half filled electronic configuration in its p- orbital i.e. 2s² 2p³ which is relatively more stable. Hence N has the highest 1 E₁.

Out C, Sb, Mg and Mn, carbon is highly electronegative and is a non metal, Sb is metalloid, Mg is a typical metal and Mn is a transition metal. Their oxides will be CO₂ weakly (acidic ) Sb₂O₃ ( amphoteric), MgO (distinctly basic) and Mn₂O₃ (basic). Therefore, the only oxide which is amphoteric is Sb₂O₃ .

As the electronegativity of the elements decreases from top to bottom down the group, the basic character of M₂O₃ (M = element of nitrogen family) increases.