The total number of correct orders is: (i) Z n 2 + AlF₃ (Melting point) (iii) AgI AgCl (Color intensity) (iv) ZnCl₂

Question

The total number of correct orders is:

(i) $Z n^{2 +}$ < $C d^{2 +}$ < $H g^{2 +}$ (Number of d-electrons)

(ii) NaF > MgF₂ > AlF₃ (Melting point)

(iii) AgI > AgCl (Color intensity)

(iv) ZnCl₂ < HgCl₂ (Degree of ionization in aqueous solution)

(v) Na₂CO₃ < MgCO₃ (Temperature required for thermal decomposition)

TestHub · Accepted Answer

(i) Correct: The total number of d-electrons increases down the group ( $Z n^{2 +}$ = 10, $C d^{2 +}$ = 20, $H g^{2 +}$ = 30).

(ii) Incorrect: Due to higher lattice energy, the correct melting point order is $N a F < M g F_{2} < A lF_{3}$ .

(iii) Correct: Due to greater polarization and covalent character (Fajans' rule), $A g I$ (dark yellow) has a higher color intensity than $A g Cl$ (white).

(iv) Incorrect: $H g Cl_{2}$ is highly covalent and barely ionizes in water, so the degree of ionization is $Z n Cl_{2} > H g Cl_{2}$ .

(v) Incorrect: Alkali metal carbonates are more thermally stable than alkaline earth metal carbonates, so $N a_{2} CO_{3} > M g CO_{3}$ .

Chemistry - CHEMICAL BONDING Question with Solution | TestHub

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JEE Main 2027 (Class 12)