Chemistry | VITEEE 2015 | Discussion Page

Point out incorrect stability order

$[Cu(NH_{3})_{4}]^{2+} < [Cu(en)_{2}]^{2+} < [Cu(trien)]^{2+}$

$[{Fe(H_{2}O})_{6}]^{3+}< [Fe(NO_{2})_{6}]^{3-}<[Fe(NH_{3})_{6}]^{3+}$

$[{Co(H_{2}O})_{6}]^{3+} <[Rh(H_{2}O)_{6}]^{3+}<[Ir(H_{2}O)_{6}]^{3+}$

$[{Cr(NH_{3}})_{6}]^{+} <[Cr(NH_{3})_{6}]^{2+}<[Cr(NH_{3})_{6}]^{3+}$

Option B

Increasing order of stability

(a) $[Cu(NH_{3})_{4}]^{2+}< [Cu(en)_{2}]^{2+}<[Cu(trien)]^{2+}$

Their formation of entropy increases in the same order. Ligand denticity is increased

(b) $[{Fe(H_{2}O})_{6}]^{3+}< [Fe(NO_{2})_{6}]^{3-}<[Fe(NH_{3})_{6}]^{3+}$

$\because$ NH₃ is weaker ligand than NO₂^-

$\therefore$ The correct stability order is

$[{Fe(H_{2}O})_{}]^{3+} <[Fe(NH_{3})_{6}]^{3+}<[Fe(NO_{2})_{6}]^{3-}$

Z_eff value increases from Co³⁺ to Ir³⁺

(d) $[{Cr(NH_{3}})_{6}]^{+} <[Cr(NH_{3})_{6}]^{2+}<[Cr(NH_{3})_{6}]^{3+}$

O.S of Cr atom increases from +1 to +3

Discussion Forum