I intend to make the following composition of copper plating solution:
\begin{array}{c:c} \rm material & \rm concentration \\\hline \rm Copper sulfate & \pu{200 \frac{g}{L}} \\ \rm sulfuric~acid & \pu{100 \frac{g}{L}} \\ \ce{Cl-} & \pu{50 ppm} \\ \end{array}

Do I use pure $\ce{H2SO4}$ ($95$–$98~\%$) and pure $\ce{HCl}$ ($37~\%$)?

Please check if I am correct with calculation.

first, copper sulfate: $$\pu{200 g} \times 5 = \pu{1000g}$$ then ($98~\%$) $\ce{H2SO4}$: $$\pu{100 \frac{g}{L}} \times \frac{\pu{5 L}}{\rm 1.84 g.ml^{-1}~ (\rho~of~H2SO4)} = \pu{271 \frac{ml}{L}}$$ then use ($37~\%$) $\ce{HCl}$: $$\pu{0.05 g/L} (= \pu{50ppm}) \times \pu{5L} \times \pu{1.19 g/mL}\ (\rho~ \text{of}\ \ce{HCl}) = \pu{0.21 ml/L}$$

so $$\pu{5000ml} - \pu{1000ml} - \pu{271ml} - \pu{0.21ml} = \pu{3728.79 ml}$$ — fill up this much water at final


1 Answer 1


I don't know what you are plating (nor do I care...) but here are some general observations.

(1) Plating is messy and exacting analytical measurements are overkill. Your calculation of 3728.79 ml water for instance is wild. I'm not sure what you intend to use for a container, but just diluting to 5 l +/- 100 ml would be more than enough precision.

(2) It is unclear if 200 g/l for copper sulfate is anhydrous copper sulfate or the pentahydrate. You're near the saturation limit for dissolving anhydrous copper sulfate at room temperatures.

(3) Your sulfuric acid calculation has the right number but wrong units. You need 271 ml per 5 liters.

SAFETY: You will require eye protection and appropriate clothing. When diluting sulfuric acid always add the sulfuric acid to the water. The reaction is very exothermic. (If you try to add water to the acid it will boil violently and splatter sulfuric acid which is more than extremely dangerous.)

You should also not work alone, and you should have some sort of plan as to how you would handle an accident. What are you going to do if you get acid in your eye, or what happens if you drop the bottle of sulfuric acid? It turns out that concentrated sulfuric acid is very slippery...

(4) Your hydrochloric acid calculation is wrong. You have the right density, but HCl acid is only 37% HCl, the rest is water. Also HCl is only 97.3 % Cl, that pesky H is the rest. Your calculation is also again for 5 liters not 1 so the units that you show are wrong. I'm not sure about copper sulfate, but it wouldn't surprise me if there were some chloride in the sulfate. That little hydrochloric acid isn't going to change the acidity of the solution. I'd be tempted to use copper (II) chloride as the source of chloride. It stores a lot easier, and would be easily measured. (Hydrochloric acid releases HCl fumes unless absolutely sealed - like in a glass ampule.)


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