Question

A compound is made by mixing cobalt (III) nitrite and potassium nitrite solutions in the ratio of 1 : 3. The aqueous solution of the compound showed 4 particles per molecule whereas molar conductivity reveals the presence of six electrical charges. The formula of the compound is :

• A. Co(NO2)3 . 2KNO2
• B. Co(NO2)3 . 3KNO2
• C. K3[Co(NO2)6]
• D. K[Co(NO2)4]

Answer 1

Answer: (C)

K3$Co(NO2)6$

Answer 2

Co(NO2)3 + 3KNO2 $\longrightarrow$ K3[Co(NO2)6] 3K+ + [Co(NO2)6]3– (total six electric charge)

3 : 1 electrolyte