Chemistry : The p-Block Elements

If radium and chlorine combine to form radium chloride, the compound would be

• half as radioactive as radium

• twice as radioactive

• as radioactive as radium

• not radioactive

Which of the following arrangements is correct in respect of solubility in water?

• CaSO₄ > BaSO₄ > BeSO₄ > MgSO₄ > SrSO₄

• BeSO₄ > MgSO₄, > CaSO_4, > SrSO_4, > BaSO₄

• BaSO₄> SrSO₄ > CaSO₄ >MgSO₄ > BeSO₄

• BeSO₄ > CaSO₄, > MgSO₄ >SrSO₄ > BaSO₄

The order of equivalent conductances at infinite dilution for LiCl, NaCl and KCl is

• LiCl > NaCl > KCl

• KCl > NaCl > LiCl

• NaCl > KCl > LiCl

• LiCl > KCl > NaCl

Compound X is tested and the results are shown in the table.

Test	Result
Aqueous sodium hydroxide is added, then heated gently.	Gas given off which turns damp red litmus paper blue
Dilute hydrochloric acid is added.	Effervescence, gas given off which turns lime water milky and acidified K2Cr2O7, paper green.

Which ions are present in compound X?

• Ammonium ions and sulphite ions

• Ammonium ions and carbonate ions

• Sodium ions and carbonate ions

• Ammonium ions and sulphate ions

Sulphuryl chloride (SO₂Cl₂) reacts with white phosphorus (P₄) to give

• PCl₅, SO₂

• OPCl₃, SOCl₂

• PCl₅, SO₂, S₂Cl₂

• OPCl₃, SO₂, S₂Cl₂

Ionisation potential values of noble gases decrease down the group with increase in atomic size. Xenon forms binary fluorides by the direct reaction of elements. Identify the correct statement(s) from below.

• Only the heavier noble gases form such compounds

• It happens because the noble gases have higher ionisation energies

• It happens because the compounds are formed with electronegative ligands

• Octet of electrons provide the stable arrangements 

If Cl₂ is passed through hot aqueous NaOH, the products formed have Cl in different oxidation states. These are indicated as

• -1 and +1

• -1and +5

• +1 and +5

• -1and +3

The hydrides of the first elements in groups 15-17, namely NH₃, H₂O and HF respectively show abnormally high values for melting and boiling points. This is due to

• small size of N, O and F

• the ability to form extensive intermolecular H-bonding

• the ability to form extensive intramolecular H-bonding

• effective van der Waals' interaction

Among the following observations, the correct one that differentiates between ${\mathrm{SO}}_3^{2-}$ and ${\mathrm{SO}}_4^{2-}$ is

• both form precipitate with BaCl₂,${\mathrm{SO}}_3^{2-}$ dissolves in HCl but ${\mathrm{SO}}_4^{2-}$ does not.

• ${\mathrm{SO}}_3^{2-}$ forms precipitate with BaCl₂,${\mathrm{SO}}_4^{2-}$ does not.

• ${\mathrm{SO}}_4^{2-}$  forms precipitate with BaCl_2, ${\mathrm{SO}}_3^{2-}$does not

• both form precipitate with BaCl_2, ${\mathrm{SO}}_4^{2-}$ dissolves in HCl but ${\mathrm{SO}}_3^{2-}$ does not.

'Sulphan' is

• a mixture of SO₃ and H₂SO₅

• 100% conc. H₂SO₄

• a mixture of gypsum and conc. H₂SO₄

• 100% oleum (a mixture of 100% SO₃ in 100% H₂SO₄)