1. Place about 3ml of 0.1 M chromium III chloride solution into a test tube and record the color. Add drops of 2M sodium hydroxide until a precipitate of Cr(OH)3 first forms.
2. Add more drops of sodium hydroxide until the precipitate dissolves to form the complex ion [Cr(OH)4]^-.
Write an equation for this reaction
1. CrCl3(aq) + 3NaOH(aq) → Cr(OH)3(s) + 3NaCl(aq)
2. Cr(OH)3(s) + NaOH(aq) → [Cr(OH)4]^-(aq)
Write the complete equation
1. CrCl3(aq) + 3NaOH(aq) → Cr(OH)3(s) + 3NaCl(aq)
2. Cr(OH)3(s) + NaOH(aq) → Na[Cr(OH)4](aq)
The equation for the reaction is as follows:
CrCl3 + 4NaOH → Na[Cr(OH)4] + 3NaCl
To write the equation for the reaction between chromium III chloride and sodium hydroxide, we need to first determine the chemical formulas of the reactants and products involved.
The chemical formula of chromium III chloride is CrCl3, indicating that it contains one chromium ion (Cr3+) and three chloride ions (Cl-).
The chemical formula of sodium hydroxide is NaOH, representing one sodium ion (Na+) and one hydroxide ion (OH-).
1. Reaction with sodium hydroxide to form chromium(III) hydroxide (Cr(OH)3):
Cr3+(aq) + 3OH-(aq) --> Cr(OH)3(s)
In this first step, when sodium hydroxide is added to the chromium III chloride solution, the hydroxide ions (OH-) react with the chromium ions (Cr3+) to form a precipitate of chromium(III) hydroxide (Cr(OH)3).
2. Reaction of chromium(III) hydroxide with excess sodium hydroxide to form the complex ion [Cr(OH)4]^-
Cr(OH)3(s) + OH-(aq) --> [Cr(OH)4]^-(aq)
In the second step, by adding more drops of sodium hydroxide, the precipitate of chromium(III) hydroxide dissolves due to the formation of the complex ion [Cr(OH)4]^-. The hydroxide ions react with the chromium(III) hydroxide to form the complex ion, which remains in solution.
Overall equation for the reaction:
Cr3+(aq) + 4OH-(aq) --> [Cr(OH)4]^-(aq)
This equation represents the overall reaction between chromium III chloride and sodium hydroxide, where one chromium ion reacts with four hydroxide ions to form the complex ion [Cr(OH)4]^- in solution.