Question

In the presence of aqueous ammonia, cobalt(III) forms the complex ion Co(NH3)63+. Determine the molar concentration...

In the presence of aqueous ammonia, cobalt(III) forms the complex ion Co(NH3)63+. Determine the molar concentration of free cobalt(III) ion in solution when 0.170 mole of Co(NO3)3 is dissolved in a liter of 2.50 M aqueous ammonia.

Homework Answers

Answer #1

The formation constants are very large. Since Kf is large, assume all the Co3+ is consumed and converted to complex ion, Co(NH3)63+.

We can determine the concentration of Co3+ ions produced by the subsequent dissociation of the complex ion.

The formation constant 'Kf' for the complex ion, Co(NH3)63+ is 5.0 1031

[NH3] = 2.50 – 6 0.170 = 1.48

Co3++ 6 NH3   Co(NH3)63+

0 1.180 170

x +6x -x

x 1.48 + 6x 0.170–x

Since x will be small, 1.48 + 6x ≈ 1.48 and 0.170–x ≈ 0.170

Kf = 5.00 x 1031= [Co(NH3)63+]/([Co3+][NH3]6)

Rearranging the above equation,

[Co3+] = [Co(NH3)63+]/(NH3]6 Kf) = 0.170 /1.486/5.00 x 1031 = 3.23 x 10-34

Know the answer?
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Not the answer you're looking for?
Ask your own homework help question
Similar Questions
In the presence of aqueous ammonia, cobalt (III) forms the complex ion Co(NH3)6 3+. Determine the...
In the presence of aqueous ammonia, cobalt (III) forms the complex ion Co(NH3)6 3+. Determine the molar concentration of free cobalt (III) ion in solution when 0.250 mole of Co(NO3)3 is dissolved in a liter of 2.50 M aqueous ammonia.
A solution contains 0.0500 M Co3 (aq), 0.0230 M S2–(aq), and 2.45 M NH3. Cobalt(III) ions...
A solution contains 0.0500 M Co3 (aq), 0.0230 M S2–(aq), and 2.45 M NH3. Cobalt(III) ions in aqueous solutions complex with NH3 to produce Co(NH3)63 . (Kf = 5.0 x 1031) What will be the concentration of Co3 (aq) when Co(NH3)63 forms?
A solution contains 0.0500 M Co3 (aq), 0.0280 M S2–(aq), and 1.85 M NH3. Cobalt(III) ions...
A solution contains 0.0500 M Co3 (aq), 0.0280 M S2–(aq), and 1.85 M NH3. Cobalt(III) ions in aqueous solutions complex with NH3 to produce Co(NH3)63 . (Kf = 5.0 x 1031) What will be the concentration of Co3 (aq) when Co(NH3)63 forms? [Co3] = M Will Co2S3 precipitate? (Ksp = 4.0 x 10–21) yes/no
A solution contains 0.0500 M Co3 (aq), 0.0270 M S2–(aq), and 1.65 M NH3. Cobalt(III) ions...
A solution contains 0.0500 M Co3 (aq), 0.0270 M S2–(aq), and 1.65 M NH3. Cobalt(III) ions in aqueous solutions complex with NH3 to produce Co(NH3)63 . (Kf = 5.0 x 1031) (Part 1) What will be the concentration of Co3 (aq) when Co(NH3)63 forms? (Part 2) Will Co2S3 precipitate? (Ksp = 4.0 x 10–21)​
A solution contains 0.0500 M Co^3+ (aq), 0.0290 M S^2–(aq), and 1.65 M NH3. Cobalt(III) ions...
A solution contains 0.0500 M Co^3+ (aq), 0.0290 M S^2–(aq), and 1.65 M NH3. Cobalt(III) ions in aqueous solutions complex with NH3 to produce Co(NH3)6^(3+) . (Kf = 5.0 x 10^31) What will be the concentration of Co3 (aq) when Co(NH3)6^3+ forms? Will Co2S3 precipitate? (Ksp = 4.0 x 10–21)
In the presence of excess OH-, the Zn2+(aq) ion forms a hydroxide complex ion, Zn(OH)42-. Calculate...
In the presence of excess OH-, the Zn2+(aq) ion forms a hydroxide complex ion, Zn(OH)42-. Calculate the concentration of free Zn2+ ion when 1.46×10-2 mol Zn(CH3COO)2(s) is added to 1.00 L of solution in which [OH- ] is held constant (buffered at pH 12.80). For Zn(OH)42-, Kf = 4.6×1017.
Cobalt forms two common ion oxidation states, Co+3 and Co+3. When solid cobalt is reacted with...
Cobalt forms two common ion oxidation states, Co+3 and Co+3. When solid cobalt is reacted with a gold (III) chloride solution, two reactions are possible, as shown in the following equations: Reaction 1) AuCl3 (aq)  + Co(s)  → Au(s)  + CoCl3 (aq) Au+3(aq)  + Co(s)  →   Au(s)  + Co+3(aq) Reaction 2) 2 AuCl3 (aq)  + 3 Co(s)  →   2 Au(s)  + 3 CoCl2 (aq) 2 Au+3(aq)  + 3 Co(s)  →   2 Au(s)  + 3 Co+2(aq) If reaction 2 is correct how many grams of solid gold (MW = 196.967) will be produced...
The cobalt(III) complexes [CoF6]3-, [Co(NH3)6]3+, and [Co(CN)6]3- have the colors orange, green, and yellow. Which complex...
The cobalt(III) complexes [CoF6]3-, [Co(NH3)6]3+, and [Co(CN)6]3- have the colors orange, green, and yellow. Which complex do you expect to appear which color? Explain your reasoning.
Determine the molar solubility (in M to two decimal places) of solid cobalt(II) hydroxide(ksp=5.92 x 10^-15)...
Determine the molar solubility (in M to two decimal places) of solid cobalt(II) hydroxide(ksp=5.92 x 10^-15) when dissolved in: a) an aqueous solution containing 0.1 M NaOH. & b) in water (@25 degrees C)
The complex ion Cu(NH3)42 is formed in a solution made of 0.0300 M Cu(NO3)2 and 0.400...
The complex ion Cu(NH3)42 is formed in a solution made of 0.0300 M Cu(NO3)2 and 0.400 M NH3. What are the concentrations of Cu2 , NH3, and Cu(NH3)42 at equilibrium? The formation constant*, Kf, of Cu(NH3)42 is 1.70 × 1013. This is what the hint gave me, Since the formation constant, Kf, is very large, it can be assumed that the reaction goes nearly to completion to form Cu(NH3)42 . Cu2 is the limiting reagent and will be used up...