Question

The synthesis of Nitro-and nitritopentammino cobalt(III) chloride.

Write the balnced reaction equations of both isomer formations.

Caluclate the theoretical yield for the formation of isomer 1(nitropentoammino cobalt (III) chloride) and isomer 2( nitriotopentammino cobalt (III) chloride) , if 2.5 g of pentammine complex of cobalt(III) chloride was used for the formation of both isomers.

Answer 1

[Co(NH₃)₅Cl​]Cl₂ + NaNO₂ [Co(NH₃)₅(NO₂)]Cl₂ [Co(NH₃)₅(ONO)]Cl₂

In the case of concentrated solution in ammonia, nitro-isomer is obtained, whereas in the case of diluted solution of ammonia, nitrito-isomer is obtained.

2.5 g of [Co(NH₃)₅Cl]Cl₂ = 2.5 g/(250.438 g/mol) ~ 0.01 mol

Nitro isomer: The theoretical yield of [Co(NH₃)₅(NO₂)]Cl₂ = 41%

i.e. (41/100)*0.01 mol = 0.0041 mol

Therefore, the theoretical yield of [Co(NH₃)₅(NO₂)]Cl₂ = 0.0041 mol * 260.993 = 1.07 g

Nitrito isomer: Now, the theoretical yield of [Co(NH₃)₅(ONO)]Cl₂ = 42%

i.e. (42/100)*0.01 mol = 0.0042 mol

Therefore, the theoretical yield of [Co(NH₃)₅(ONO)]Cl₂ = 0.0042 mol * 260.993 = 1.096 g