3. State the reason for the following: (10)
(i) HI has more covalent character than HCl.
(ii) Ionic compounds are more soluble in water than benzene.
(iii) The radius of S2
ion is larger than the radius of Cl
ion.
(iv) In NaBr crystal, each ion is octahedrally surrounded by ions of opposite charge.
(v) In HF, the experimental bond length value is less than the sum of covalent radii.

Answer :

(i)HI has more covalent character than HCl due to atomic size.Lager the atomic size is more stabler the atom will be.So as Iodine is larger in size than chlorine.So iodine is held more firmly by means of covalent bond than chlorine and so HI has more covalent bond.

(ii)Ionic compounds have positive and negative charged ions.So they are polar.Water being a polar solvent have the tendency to attract ions and so ionic compounds dissolve in water where as benzene is a non-polar solvent.So ionic compounds cannot dissolve in benzene.

(iii) Cl has one extra proton than S2 , So protons of Cl attract the electrons more firmly and thus the size of atom is small and radius is less.In S2 the number of protons are less than in Cl.so force of attraction between electrons and protons is a bit less than in Cl.Thus the size of S2 is large and radius is greater than Cl.

(iv)Sodium bromide structure is a face-centered cubic lattice of Na+ ions interlocked with similar lattice of Cl- ions.The unit cell of sodium bromide consists of 14 bromide ions and 13 sodium ions.Each bromide ion is surrounded by six sodium ions and each sodium ion is surrounded by six bromide ions.Thus it is arranged octehedrallly.

Other Questions